5 Speed gearbox flaw repair

[DMC-81]

Hi there,

I recently learned about one of the flaws in our 5-speed manual gearbox when the secondary shaft nut bored through the rear cover and dumped the gear oil out on the ground. :what_the:
47585

After taking my first ride of shame back home, I was able to repair it without removing the gearbox, and I'll post my adventure in this thread. But after the repair, I am guessing that the second gear rollpin had been bent or sheared in the event, as I recall it went into second hard when the nut backed off. After the repair, second gear engages normally, but now it sometimes pops out and I have a slight gear grinding noise when I'm not in second gear. I parked the car right away after diagnosing, but now I'll have to take the gearbox out to repair it.:swear1:

Looking on the bright side, I'll be able to address other things like the rear main seal, the pilot bearing, check/replace the clutch, replace the axle boots and lip seals etc. Again, I'll post my work in this thread.

I have yet to remove the gearbox, but I have some questions for the community in advance :

1) Please share any special considerations/advice on removing the gearbox. I have and will follow the Workshop Manual, have watched the Wheeler Dealer episode, and I know to support the drive axles when removing them.

2) Who carries/ stocks a reinforced second gear rollpin?

3) Are there any other rollpins that I should replace with the reinforced version?

4) Assuming I have damage to the gears for second gear, who has stock?

5) What are your opinions on who carries a good quality rear main seal (with the ribs) pilot bearing, etc.

Thanks a bunch.

[dn010]

Looks like the nut broke free from the shaft on you. I have removed and rebuilt the transmission on my car many times, familiarize yourself with the manual for removal and you'll be fine and check things off as you go, it is easy to forget about the back up wiring. If you need a clutch, now is the time as well. I was able to do this on the floor with a notched piece of 4x4 on a floor jack. If you have a lift, even better...

I don't have any advice past #1, I would love to work on mine at the same time, I have an annoying grind every time I shift into second I'd love to get rid of! I can tell you I got all my transmission gut parts from Rob Grady more than a decade ago, give him a shout.


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[David T]

The roll pin is not necessarily bent. When replacing the roll pin there is no "strengthened" roll pin but what we do now is after replacing the roll pin we put a smaller one inside the replaced roll pin. That makes it stronger. All of the vendors should have the regular pin and the smaller one. What bends the roll pin is forcing shifts, usually because of a problem in the clutch hydraulics. When removing the transaxle remove the oil BEFORE taking it out. Getting those little covers off of the bell housing is a pain in the a--. Support the motor after taking the transaxle out. Internal parts like gears for the transaxle are hard to get and expensive but you should not need any. All of the vendors can get quality parts but in some cases you may want good, used ones and not all vendors have that. Before removing the transaxle try Redline MT-90 and recheck your linkage adjustments.

[PJ Grady Inc.]

Hi there,

I recently learned about one of the flaws in our 5-speed manual gearbox when the secondary shaft nut bored through the rear cover and dumped the gear oil out on the ground. :what_the:
47585

After taking my first ride of shame back home, I was able to repair it without removing the gearbox, and I'll post my adventure in this thread. But after the repair, I am guessing that the second gear rollpin had been bent or sheared in the event, as I recall it went into second hard when the nut backed off. After the repair, second gear engages normally, but now it sometimes pops out and I have a slight gear grinding noise when I'm not in second gear. I parked the car right away after diagnosing, but now I'll have to take the gearbox out to repair it.:swear1:

Looking on the bright side, I'll be able to address other things like the rear main seal, the pilot bearing, check/replace the clutch, replace the axle boots and lip seals etc. Again, I'll post my work in this thread.

I have yet to remove the gearbox, but I have some questions for the community in advance :

1) Please share any special considerations/advice on removing the gearbox. I have and will follow the Workshop Manual, have watched the Wheeler Dealer episode, and I know to support the drive axles when removing them.

2) Who carries/ stocks a reinforced second gear rollpin?

3) Are there any other rollpins that I should replace with the reinforced version?

4) Assuming I have damage to the gears for second gear, who has stock?

5) What are your opinions on who carries a good quality rear main seal (with the ribs) pilot bearing, etc.

Thanks a bunch.

We have everything you need including the reinforced roll pin, 1st/2nd slide hubs and gears, shift forks, seal kits, Valeo clutch kits, sleeved hydraulics that last etc. I have rebuilt many UN1's and can get you out of trouble if you need help.
Rob

[dn010]

If you take it apart, just remember to put the damn differential back In the correct way. I made that mistake once, cost me 8 hours of time!


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[PJ Grady Inc.]

If you take it apart, just remember to put the damn differential back In the correct way. I made that mistake once, cost me 8 hours of time!


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Sage advise. Strong hint....DO NOT FOLLOW DMC Workshop Manual F:06:02 Figure 14 which clearly illustrates the ring gear fitted to the wrong case half. What where they thinking?
Rob

[Nicholas R]

If you get the transmission out and apart an need any help, let me know and I can stop by sometime to help you out. I've taken apart quite a few and have some spare parts as well. Its pretty straightforward though so I'd be surprised if you had any issues. :biggrin:

The transmission is pretty stout internally; I think it's pretty unlikely that you damaged any of the gears. Luckily, it will be obvious once you have it open.

What happened to your damaged 5th gear cover? Did you weld repair it or did you replace it?

[David T]

Sage advise. Strong hint....DO NOT FOLLOW DMC Workshop Manual F:06:02 Figure 14 which clearly illustrates the ring gear fitted to the wrong case half. What where they thinking?
Rob

DMC probably just copied that illustration right out of the Renault manual not realizing the orientation was wrong. It is obvious DMC did not put a lot of effort into creating technical documentation. If you think the DMC stuff is bad you should see other small manufacturers. Everything is a 2 step process, step 1, remove. Step 2 replace. All of the details are left to the reader's imagination.

[PJ Grady Inc.]

I've read that they had their own illustrator for the manual. Someone should have brought him up to speed. What would Barrie Wills say!
Rob

[DMC5180]

Dana,

Will you use a lift or just jack stands? I have photos of the last time I installed my transmission using jack stands if your interested in that method.


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[David T]

Dana,

Will you use a lift or just jack stands? I have photos of the last time I installed my transmission using jack stands if your interested in that method.


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If you use jackstands you can do it with a floor jack. If you use a lift you need a transmission jack.

[DMC-81]

Thank you for all the great advice and encouragement! I'll definitely reach out to Rob and or Nick when the time comes.

I'll double check that the linkage is right before I tackle the removal. The only thing that would have been disturbed is the fit between the extension (#108295 (http://store.delorean.com/p-8633-extension.aspx)), the crossgate clevis (#105783 (http://store.delorean.com/p-8648-clevis-mt-crossgate.aspx)), and the the control shaft assembly (#103130 (http://store.delorean.com/p-8589-control-shaft-assy.aspx)). There were two bolts fastening these 3 parts together (see pic) and there was a little bit of play in the non threaded holes on 2 of these parts that would cause a slightly different orientation on reassembly.
47589

Would that cause my symptoms?


Looks like the nut broke free from the shaft on you.


What happened to your damaged 5th gear cover? Did you weld repair it or did you replace it?

Yeah, the nut (103076 (http://store.delorean.com/p-8561-nut-secondary-shaft.aspx)) backed off completely and ruined the threads on the nut. I got a new nut and gasket from DMCH and got the cover aluminum welded locally by a guy that had 41 years experience (I found out when I picked the part up he owns an early vin unrestored DeLorean).

New nut locktited, torqued and peened:
47590
Welded cover:
47591 47592

Apparently a tell tale sign that this nut is backing off is when you hear gear whine when you are in a gear and let off the gas and coast. I was hearing that in 3 and 4 but thought it was characteristic of the box and didn't ask. :facepalm:

Oh by the way the most difficult thing about this repair for me was getting the 5th gear detent screw out. I had to enlist help, and it turns out that there was a ridiculous amount of thread adhesive in there.

[DMC-81]

Dana,

Will you use a lift or just jack stands? I have photos of the last time I installed my transmission using jack stands if your interested in that method.


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I will be using jack stands and would definitely appreciate any photos.

Thanks Dennis!

[DMCMW Dave]

Oh by the way the most difficult thing about this repair for me was getting the 5th gear detent screw out. I had to enlist help, and it turns out that there was a ridiculous amount of thread adhesive in there.

Heat it up with a propane torch or heat gun. Not to melt the aluminum, but to soften the adhesive. Then use a mallet and screwdriver to "impact" it loose. Once it cracks loose it will be finger tight. It's easier if the cover is still attached to the transmission.

[DMC-81]

Heat it up with a propane torch or heat gun. Not to melt the aluminum, but to soften the adhesive. Then use a mallet and screwdriver to "impact" it loose. Once it cracks loose it will be finger tight. It's easier if the cover is still attached to the transmission.

Thanks Dave! I was too timid to use heat last time. Live and learn! :) Now I have the threads clean and the screw installed with just a bit of blue locktite. If I have to remove it again, it should be much easier. :wrenchin:

[DMC5180]

I will be using jack stands and would definitely appreciate any photos.

Thanks Dennis!

Im not sure what happened here all my photos are visible in during writing and editing of this post. I've contacted the Administrator.


These were taken with it going in. I Have headers, no crossover pipe to contend with.

I don't have a picture, but I raised the engine and inserted a short 2x2 and a small stack of door/window framing shims between the back of the oil pan and frame cradle. This keeps the engine level or even a bit tail high when the weight was let down on it. I needed to use the block method so I didn't have any obstruction from another jack where I need access to pump the trans jack handle. I'm sure I could have used a small bottle jack offset to one side of the oil pan, but I didn't have to use.

Loaded and ready to lift. I used a Motorcycle/Atv jack. (Harbor freight) It cradled the transmission perfectly with a little blocking to level tranny.. I loaded the transmission onto the jack in location. The Jack stands were at full extension but was not quite high enough to roll the everything under at once.

47594

These photos loaded out of sequence but you get the idea.

Centerforce clutch with finger weights. If you do the rear main seal but don't replace the clutch, you need to get a clutch disc alignment tool. I made one years ago of of aluminum round stock (un-splined)
47601


A refurbished clutch fork. Note: Its a good idea to remove the fork and lube the pivot ball and socket with a mixture of 50/50 moly grease and anti seize compound. (Rob Grady tip) Rob also has the rubber cup/cover seal if you need a fresh replacement. I'm guessing all the DMC vendors have it though.

47600


I bought some longer M10 x 1.50 bolts and cut the heads of to use as alignment dowels in the lower bolt locations.

4759947598


Up Up and IN. My wife did the heavy lifting while I guided things in place. It makes a difference to have a helper for 5 minutes.
47597

The perfect time to replace the fuel filter while its easily accessible before the trans went back in.

47596


Driver side shot ready to go up.

47595

Gut shots

4760347602

The infamous second gear roll pin in the notch of the fork.
47604

Reverse gear

47605

[DMC-81]

Thanks for the detailed information Dennis! :thumbup: Hopefully an admin can fix the pictures.

Today I double checked/adjusted the linkage described above and test drove it. No joy. It's still doing the same thing. So I jacked the car up on 4 floor jacks and prepared for surgery. Tomorrow I'll get as far as possible with removing things, draining the gear oil, etc.

Question to all: is it possible to remove the clutch slave cylinder off the transmission without disassembling the line? ( ...is there enough slack in the SS flexible line to move the slave and hard line out of the way?) I'd really like to avoid having to bleed that system again.

Thanks.

[DMC5180]

Yeah, you can unbolt the line clip on the case bolt then unbolt the slave cylinder and lift it out of the notch in the bell housing. Use some zip ties to hold the metal line and slave up out of the way.


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[DMC5180]

Lets try this again.

These were taken with it going in. I Have headers, no crossover pipe to contend with.

I don't have a picture, but I raised the engine and inserted a short 2x2 and a small stack of door/window framing shims between the back of the oil pan and frame cradle. This keeps the engine level or even a bit tail high when the weight was let down on it. I needed to use the block method so I didn't have any obstruction from another jack where I need access to pump the trans jack handle. I'm sure I could have used a small bottle jack offset to one side of the oil pan, but I didn't have to use.

Loaded and ready to lift. I used a Motorcycle/Atv jack. (Harbor freight) It cradled the transmission perfectly with a little blocking to level tranny.. I loaded the transmission onto the jack in location. The Jack stands were at full extension but was not quite high enough to roll the everything under at once.

47615

47616


Up Up and IN. My wife did the heavy lifting while I guided things in place. It makes a difference to have a helper for 5 minutes.

47617


Centerforce clutch with finger weights. They don't make this version with the added weights anymore. If you do the rear main seal but don't replace the clutch, you need to get a clutch disc alignment tool. I made one years ago of of aluminum round stock (un-splined)

47618


A refurbished clutch fork. Note: Its a good idea to remove the fork and lube the pivot ball and socket with a mixture of 50/50 moly grease and anti seize compound. (Rob Grady tip) Rob also has the rubber cup/cover seal if you need a fresh replacement. I'm guessing all the DMC vendors have it though.

47619

The perfect time to replace the fuel filter while its easily accessible before the trans went back in.

47620


I bought some longer M10 x 1.50 bolts and cut the heads of to use as alignment dowels in the lower bolt locations. This works nicely for getting things lined up and square to slide forward into place. Once the upper bolts were in place, the lower locator bolts came out with finger pressure.

47621 47622

Gut shots: including infamous second gear roll pin in the notch of the shift fork.

47623 47624 47625

Reverse Gear

47626

[PJ Grady Inc.]

"A refurbished clutch fork. Note: Its a good idea to remove the fork and lube the pivot ball and socket with a mixture of 50/50 moly grease and anti seize compound. (Rob Grady tip) Rob also has the rubber cup/cover seal if you need a fresh replacement. I'm guessing all the DMC vendors have it though."

Actually not true. DMCH and therefore probably all their vendors don't carry this item. I sourced them through my European Renault sources years ago and supply a new one with every clutch we sell. This ovwerlooked item is critical to avoid the dreaded 'clutch ball squeak' that is so common with these cars.
Rob

[DMC5180]

"A refurbished clutch fork. Note: Its a good idea to remove the fork and lube the pivot ball and socket with a mixture of 50/50 moly grease and anti seize compound. (Rob Grady tip) Rob also has the rubber cup/cover seal if you need a fresh replacement. I'm guessing all the DMC vendors have it though."

Actually not true. DMCH and therefore probably all their vendors don't carry this item. I sourced them through my European Renault sources years ago and supply a new one with every clutch we sell. This ovwerlooked item is critical to avoid the dreaded 'clutch ball squeak' that is so common with these cars.
Rob

Rob, Thanks for clarifying that. To be clear, you are speaking of the rubber grease Cup Seal?

[PJ Grady Inc.]

Rob, Thanks for clarifying that. To be clear, you are speaking of the rubber grease Cup Seal?
Yes 103251G is the # we use for it.

[DMC-81]

Thanks again Dennis! Those pictures and techniques are very helpful.

Today I drained the gear oil for (the second time in a month.... so the inside should be clean), and removed the drive axles. The first one took over an hour as I used a normal ratchet on the M10 bolts, and the outboard side was stuck after I removed the bolts. I eventually I took a piece of 2x2 wood and placed it on the thick metal disc that the bolts pass through. Then I tapped the wood sharply with a hammer. The axle broke free from the flange after that, so it was just stuck.

The second axle only took 10 minutes as I used an air impact wrench, and the tapping technique to release it.

2 of the 4 boots were cracked at the outboard bigger clamp, so their refurbishment is just in the nick of time.
47631

Question: were the axles painted originally? If so, was it gloss or satin black? I see the picture on DMC's website seems to indicate black paint.

[DMC5180]

Dana,

You know the thing to do is disassemble them and have the shafts powder coated satin black. You just mask off what doesn't get coated. [emoji16]


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[BABIS]

"A refurbished clutch fork. Note: Its a good idea to remove the fork and lube the pivot ball and socket with a mixture of 50/50 moly grease and anti seize compound. (Rob Grady tip) Rob also has the rubber cup/cover seal if you need a fresh replacement. I'm guessing all the DMC vendors have it though."

Actually not true. DMCH and therefore probably all their vendors don't carry this item. I sourced them through my European Renault sources years ago and supply a new one with every clutch we sell. This ovwerlooked item is critical to avoid the dreaded 'clutch ball squeak' that is so common with these cars.
Rob
Rob, Thanks for clarifying that. To be clear, you are speaking of the rubber grease Cup Seal?

Hello guys, do you have a pic of the #103251 grease cup installed? since I am experiencing the dreaded "squeak" I am pretty sure they didn't install anything like that when they did my clutch..

[DMC-81]

Well, it's been a while. I disconnected most things to remove the gearbox but didn't feel confident to actually remove it by myself. I knew I needed help.... Then I got the fantastic news that DMCFL was moving to Orlando. So, I decided to wait.
On the weekend I delivered my baby to Tony and his familiar team to get that help.

49359

Wow, the construction/ finish work is coming along, and looks awesome! It's just like I'd do it in my perfectionistic tendencies. It's like my Stainless icon is in its second home. The place was filling up fast with cars. The tow truck driver said "it looks like they're collecting DeLoreans!"

Thanks Tony and team! :wiggle:

P.S. Lenny, your car looks great!

Now I can continue this thread...

[DMC-81]

With my starter and exhaust refurbed already, I focused on the drive axles while my car is queued for attention at DMCFL.

After great informational posts here warning about a messy job on the CVs, I set up a table with a plastic sheet to control the grease as I refurb them...also gloves, many paper towels, and a garbage can nearby. I used a small piece of 1x2" wooden block ( to avoid damage) and a hammer to remove the flange/cover. It was sealed with blue Hylomar, and after I removed it, I gently scraped its residue off both parts.

49376

I used this reference photo to reassemble the joint later... i.e. how the inner race aligns with the outer race, thin versus thick edges, etc.

49377

I used a pair of snap ring pliers and a pick to remove the snap ring. The inner race came off the axle easily, and I separated the parts. After I wiped most of the grease off the parts I then bathed them in mineral spirits twice.

49378

Clean parts. I scrubbed the flanges with a blue Scotch Brite pad...

49379

I cleaned up the area and organized my parts for assembling the CV joints.
49383

Rich_NYS pointed this out for me in his resto thread...for the inner races, the smooth side on the left butts against the snap ring, and the other side on the right with the raised area butts against the axle.

49380

One CV dry assembled. I paid attention to the proper orientation of the inner and outer races, and made sure that the smooth side of the inner race was facing me...
49381

And so on. I bagged and tagged each joint's parts to keep them in the same spot on the car...
49382


The next step was refurbing and painting the axle rods. I must say that this whole task would be fairly daunting without great resources here, and other owners who have shared their experiences. Thanks all!

[Morpheus]

Few jobs on this car are as messy and give you a sense of accomplishment as re-doing the CV joints. Nice work so far!

[Nicholas R]

I expected to see far more grease all over the place. Something a little more like this (my CV rebuild aftermath) 49420

I'll never figure out how you always manage to keep everything so clean and tidy! Very well done!! :thumbup:

[Rich_NYS]

I expected to see far more grease all over the place. Something a little more like this (my CV rebuild aftermath) 49420

I'll never figure out how you always manage to keep everything so clean and tidy! Very well done!! :thumbup:

+1


The guys at DMCNW are probably having their lunch on his frame.....it's so clean you could eat off it.

[DMC-81]

Thanks for the kind words guys!!

Well, I finished the axles..

Before..
49424

I wet sanded them with 320 grit sandpaper and oxalic acid until the rusty residue was gone, then more wet sanding with mineral spirits. I used a twisting motion around the circumference of the axle to preserve the lathe lines...
49425

A paint booth made out of a box.. a brilliant idea for painting these heavy rods that I got from Rich_NYS. I taped the ends and cleaned them with isopropyl alcohol before painting.
49426

2 coats of self etching primer. I just sprayed, turned, and repeated...
49427

4 coats of epoxy paint...
49428

All dried and cured..

49429

[DMC5180]

Dana,

If you need a perfectionist goal to shoot for, you're in the right shop. In 2012 Tony brought his personal car to DCS Orlando for Concourses judging. This was the 2nd time he had entered that judging competition. The first Was 2003 at a DMCH open house. I was on the judging team for both events. In 2003 I did the undercarriage portion. While it was an excellent example of a low mile car , it had been driven and was not perfect, but still ended up taking first place due to bonus points given for dealer options. In the year or two leading up to DCS Orlando. He did a full frame off cleaning and restoration for the Orlando Show. He even went above and beyond by bringing in a Stinger 4 post lift so all could see the underside completely. It was jaw dropping flawless. I think he keeps the car in a hermetically sealed room these days. [emoji6]


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[DMC-81]

Thanks Dennis. That would have been cool to see. I bought my car from Tony in 2013, as a running restoration candidate.. that's what I was looking for. Then I began taking reference pictures of the excellent specimens on the showroom to help me on my journey. I also got a copy of the magazine that his car was featured in, showing pictures of the frame off process. That totally inspired me, and I said to my wife that I was going to take my time and hopefully do the restoration right.

I'm super happy that DMCFL is now in Orlando. I met his team and they are not just employees... that are owners and enthusiasts. I'm totally comfortable having my baby there... and that's a rare thing for me to say! :thumbup:

[Rich_NYS]

I just realized your car is at DMCFL, not DMCNW...I misread "Tony" as "Toby" -lol

[DMC-81]

Well, I repacked the grease and finished the axles...

Re-greasing started with Mobil 1 Synthetic Grease. I applied it using a grease gun with a flexible tip, and a plastic spatula to press the grease down into the bearing race.
49497

Then more grease and attaching the axle..
49496

Filling and packing the other side. I wound up using 6 oz per CV...
49498

I used blue RTV in place of Hylomar to seal the cover, and placed all 6 bolts in the holes to ensure it was oriented correctly before I tapped it into place...
49500

Putting on the zip ties..
49499

Both axles finished! I trimmed the inner zip tie and ground the cut metal as it was originally to avoid sharp edges. Plus I installed the new hardware..hex cap socket bolts, lock washers, and locking plates.
49501

I'm ready for the gearbox....

[powerline84]

Looks great. Nice work man .

[DMC-81]

Looks great. Nice work man .

Thanks Jimmy!

[DMC5180]

What! No concourse correct bolts. [emoji33]

J/k , using socket head bolts is smart move IMO. It's much easier to fit an Allen Socket in there than a standard 17 mm socket.


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[DMC-81]

What! No concourse correct bolts. [emoji33]

J/k , using socket head bolts is smart move IMO. It's much easier to fit an Allen Socket in there than a standard 17 mm socket.


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Ha! :) Yes, this is easier and smarter for now. I'll have the original 24 bolts and clamps replated when I get enough parts to satisfy a minimum order, and save them in case I want to have it judged. I have bagged, tagged and saved every part that I ever replaced, so if concours judging becomes important, I can make it happen. For now, I want a reliable show car.

[DMC-81]

Looks like I'll become very busy with the gearbox soon! Look at that new, clean shop at DMC FL! :hihi:

49578

[DMC-81]

The team at DMCFL removed the transmission on Friday..

49621

Today I removed the drive axle flanges, clutch fork, rear cover, and bell housing...

49622 49623 49624 49625

[DMC5180]

Why do I have this feeling, that the next photos we see will be of a nearly New looking transmission. Btw, the rubber boot that fits over the clutch fork is available from DMCH. P/N 103151


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[Rich_NYS]

Looks like I'll become very busy with the gearbox soon! Look at that new, clean shop at DMC FL! :hihi:

49578

I think they got the memo that your car is accustomed to an immaculate environment, and would be most cooperative if it was provided with similar accommodations.... :strongman: :thumbup:

[DMC-81]

Thanks guys! I'll try to make the transmission presentable...

Well, I figured out what happened. I remember that when the shaft nut backed off, I tried to shift into 2nd gear, and it went in hard. That's when I knew something was wrong. During that shift, apparently the spring that provides tension on the 2nd gear selector fork failed or jumped the roll pin and got caught up in the gears. This caused the symptoms of 2nd gear popping out, and a clicking/grinding sound. Pieces of the spring were in the selector forks, between the gears, and stuck to the case magnet....

49666 49667 49668

The good news is that the gears are pristine, and the spring (part number 103220) was in stock at the DMC Texas store. What baffles me is while the spring failed, the infamous 2nd gear roll pin was unscathed. :wow: Nevertheless, I'll replace it with a reinforced (double) pin.

49669

While I'm waiting on repair/refurbishment parts from DMC and PJ Grady, I removed the 2nd gear selector fork, repaired the slight damage to the shaft, and recovered the pieces of the spring. Props to Stephen Wynn, Rob Grady and their teams for their advice and service. Top Notch!!

49670

I also picked up my flywheel from being resurfaced..

Before
49671

After, ready for a new clutch..
49672

I also cleaned the case magnet and the mating surfaces of the case halves. Question: Do you know if the magnet is supposed to be slathered in grease, or was that just 36 years of buildup? I imagine that I have to put some on it to prevent it from falling out when I replace the case half.
49673

Thanks,

[DMC5180]

The goo on the magnet is powered metal. Its fairly common to see that to some extent. The magnet is doing it's job by collecting the particles.


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[David T]

Make sure the 5th gear fork is not bent.

[DMC-81]

The goo on the magnet is powered metal. Its fairly common to see that to some extent. The magnet is doing it's job by collecting the particles.


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Thanks Dennis.



Make sure the 5th gear fork is not bent.

Sure, I'll check it. Thanks.

[DMC-81]

Parts arrived to allow me to proceed..

49729

49730

I never was so happy to se a $1.00 part!!

49731

[DMC-81]

A gravity fed blasting gun arrived today that I bought from Eastwood, and I tried it on the bell housing. I used medium soda media, and it worked really well.

49744

I also started to replace the seals in the gearbox.

[Nicholas R]

A gravity fed blasting gun arrived today that I bought from Eastwood, and I tried it on the bell housing. I used medium soda media, and it worked really well.

49744

I also started to replace the seals in the gearbox.

Nice!! I actually bought the Harbor Freight version of that gun with sand from Lowes and did the same thing. I'm sure it was not as nice as the Eastwood one (ended up having to do some internet recommended modifications; drilling out holes to be larger and such) but it did alright. It's crazy the difference it can make.
49754
(this is not the transmission from my car, it was one I bought from a parts car hence the crazy amount of grime)

Are you going to blast the whole casing or just the bellhousing? I primed and painted mine after blasting and now it makes it super easy to keep clean because the cast aluminum isn't as porous.

[Riley88]

DMC probably just copied that illustration right out of the Renault manual not realizing the orientation was wrong. It is obvious DMC did not put a lot of effort into creating technical documentation. If you think the DMC stuff is bad you should see other small manufacturers. Everything is a 2 step process, step 1, remove. Step 2 replace. All of the details are left to the reader's imagination. hey just like the navy!

[DMC-81]

Nice!! I actually bought the Harbor Freight version of that gun with sand from Lowes and did the same thing. I'm sure it was not as nice as the Eastwood one (ended up having to do some internet recommended modifications; drilling out holes to be larger and such) but it did alright. It's crazy the difference it can make.
49754
(this is not the transmission from my car, it was one I bought from a parts car hence the crazy amount of grime)

Are you going to blast the whole casing or just the bellhousing? I primed and painted mine after blasting and now it makes it super easy to keep clean because the cast aluminum isn't as porous.

Thanks Nick! Yours looks good! Also, thanks for posting videos of the rebuilding job. It definitely makes tearing down the box easier.

I'm going to blast the whole case, one part at a time. Here are the left case half and the rear cover...

Before:
49769 49770

After:
49771 49772

I also got the last package of parts today including a NOS Renault clutch release fork from PJ Grady. Mine was looking ratty.

49773

Tomorrow I'll put the 1-2 shift rod back together with the new spring and roll pins, etc.

[DMC-81]

Today, I was able to install the new spring and the reinforced roll pins on the 1-2 shift shaft.

New pins (normal size and smaller one inside), and the old ones on the blue tape...
49813

Installed..

49814
The outside pin needed to be level with the height of the spring otherwise it would interfere with the gear below it.

Prepped and painted the input tube..

49815 49816

Cleaned the soda off the rear cover...
49818

Replaced the axle flange seal and transferred the gears to the blasted case half..

49817

Tomorrow I'll blast the last part... the other case half and replace the axle seal, then I can reassemble the gearbox.

[Rich_NYS]

Looking good Dana. That blaster seems to work well, I'm thinking of buying one to use on my fascia.

[DMC-81]

Looking good Dana. That blaster seems to work well, I'm thinking of buying one to use on my fascia.

Thanks Rich! Yeah, the blaster works pretty well for an all in one unit. You need to have good air supply and they recommend a dryer. I didn't have one, and the media got clogged up from time to time.

Well, after a looonng day yesterday, it's done, and being delivered back to DMC FL tomorrow. I'll post my last day's work very soon....

[Mark D]

Great thread so far! I've got this one bookmarked for when I pull my transmission. I've been driving with a sheared 2nd gear roll pin since I got my car in '08. One of these days I'll actually fix it.

[DMC-81]

On Sunday, I started by adjusting the orientation of the inside roll pin so that the strongest portion takes the load...
49891

Then I soda blasted the right case half...
49892 49893

After I cleaned the case half up really well, I installed the new axle seals..
49894
I used a seal puller on the old ones, and a bearing/seal driver set that I borrowed from AutoZone.

To be continued..

[DMC-81]

Continued..

I cleaned the bearing races and case mating surfaces again with Acetone and assembled the gears in the right case with Loctite 609 in the 4 bearing races. Then I immediately checked for free movement of the gears...
49895

Then it was time for Permatex Anaerobic gasket maker on the case mating surfaces...
49897

Then, quickly a final wipe of the bearing races in the other case half and Loctite 609. Plus, I put a dab of synthetic grease on the case magnet and placed it ( to prevent it from falling out ). Because it was watery, I moved the 609 up the races with a Q-tip just before mating the halves.
49898

Next, I ensured the reverse gear was all the way to the right and the shift selectors and gears were in neutral and gently mated the cases. I put 6 bolts in place and checked for gear movement and the reverse gear worked, as the gear tended to slide out of place. Then, I put all bolts in place and torqued from the inside out....
49899

Next up was the 3 bolts on the the bearing retaining plate and the 5th gear assembly. I used zip ties to keep the assembly in place in the meantime...
49900

Next was LIBERALLY applying red loctite on the shaft and nut threads, torquing to 112.5 ft/lbs, and peening the flange in the shaft indent...
49901
That was the 2nd flaw addressed.

[DMC-81]

Continued..

I cleaned the mating surfaces with Acetone and used Indian Head gasket shellac on both sides of the 2 paper gaskets for the covers. Also in this pic I put the 2 new drive axle flanges on (lubed the rubber seal and the metal contact first)...
49905

Inserted the input tube and seal, placed the clutch housing, and torqued it...
49906

Installed the rubber cup/seal, after gradually stretching the hole to fit over the pivot ball..
49907 49908

Mixed up a 50/50 "Grady goop" :) discussed earlier in the thread and applied it liberally to the pivot ball, socket, and the metal fork spring (to try and prevent corrosion). The fork spring goes in the wider slot in the ball between the seal and the cover..
49909 49910

Finally, I installed the clutch fork bellows, the slave, the throw out bearing, the 5th gear dent ball and plug, painted the speedometer plug, and refreshed the green factory paint marks....
49911

49912

49913

49914

That was Sunday. This morning, I loaded it up and delivered to DMC FL..
49915

Car and gearbox reunited..
49916

..and to think a couple years ago I was hesitant to tackle the fuel accumulator. :p

Many thanks for everyone's help and advice that made this rebuild happen in 9 days. :thankyou:

[DMC-81]

DMC FL got a lot done today.

New rear main seal and pilot bearing..
49969

Resurfaced flywheel installed..
49970

New Valeo clutch and pressure plate..
49971

Transmission back in the car. Next up is connecting accessories and what had to be removed beforehand..
49972

I just might make it to the Celebration Exotic car show this year... Fingers crossed!!

[Nicholas R]

I just might make it to the Celebration Exotic car show this year... Fingers crossed!!

You had better be there! Someone has to win "Best in Show," it might as well be you!!

[DMC-81]

You had better be there! Someone has to win "Best in Show," it might as well be you!!

Thanks Nick! Barring anything unforeseen my D will finally be there.

------------------------------

Yesterday, I picked up the car from DMCFL. They did an outstanding job! Now I'll button everything else up that I took off and refurbed.

50117

Today, I reinstalled the the diagnostic protecting plate, the crossover pipe, new O2 sensor, and finally, the drive axles, in that order. Tomorrow I'll install my refurbed starter and I'll see if it works with the new solenoid and the starter recall done. I can't wait to hear the engine with my new exhaust manifold gaskets. Plus, I haven't driven it since November. :woot:

50116

[DMC5180]

Did you have all the transmission bolts re-plated? They look very fresh.


Sent from my iPhone using Tapatalk

[Chris Burns]

Awesome work on this DMC!!:notworthy:

Love to see her at a show some day.....

[DMC-81]

Did you have all the transmission bolts re-plated? They look very fresh.


Sent from my iPhone using Tapatalk

Thanks Dennis. I didn't have time to have them replated, but it did soak (in engine degreaser) and scrub each bolt, nut, and washer.


Awesome work on this DMC!!:notworthy:

Love to see her at a show some day.....
Thanks Chris. I plan to be at Celebration.

-----------------------------

Well, I finished up the parts that had to be reinstalled, and started it today. It sounds good.

Here is the starter reinstalled..

50463

I initially had a problem with the drive axle flanges being too loose. It turned out that I missed one extra turn on the differential adjustment nut from when I counted the turns until the threads disengaged. All fixed now, and I drove it to fuel it up with non ethanol. I got the usual attention, cameras, 4 people approaching me to compliment the car, and a fist pump of a guy out the window of a passing car. :)

50462

I have a few adjustments to make, but it works.

[DMC-81]

Thanks Dennis. I didn't have time to have them replated, but it did soak (in engine degreaser) and scrub each bolt, nut, and washer.


Thanks Chris. I plan to be at Celebration.

-----------------------------

Well, I finished up the parts that had to be reinstalled, and started it today. It sounds good.

Here is the starter reinstalled..

50463

I initially had a problem with the drive axle flanges being too loose. It turned out that I missed one extra turn on the differential adjustment nut from when I counted the turns until the threads disengaged. All fixed now, and I drove it to fuel it up with non ethanol. I got the usual attention, cameras, 4 people approaching me to compliment the car, and a fist pump of a guy out the window of a passing car. :)

50462

I have a few adjustments to make, but it works.



Oh my, I typed "comment" on the car. Dang auto-correct! Oh well. I'm still adjusting the linkage, etc.

[DMC-81]

Hi there,

I need your opinions and experience...

After my rebuild, the 2nd gear popping out problem is fixed, and the shift action is smooth. However, I am getting gear noise only on deceleration/ coasting in gear. It's not present in 1st gear, but starts in 2nd, and gets progressively quieter in 3, 4 and 5. It sounds not like a whine, but like the gears are not meshing right... click click click. Its loudest in 2nd gear.

A quick Google search on other vehicles points to bearing preload. When I put the transmission back together I put the Differential Adjustment Nut in the exact same place (I believe) that I found it... 8 1/3 turns out and in.

First I thought that I had it too tight. I backed it off a little and tested it....no difference. Then today, I put it back at 8 1/3 turns, and then tightened it some. After tightening, this is how much horizontal and vertical play there is in the drive flanges...

http://youtu.be/u7cUclF5j2c

Question: is this normal, or is the drive flange not supposed to move at all?

I'll test it again tomorrow to see if tightening it some made a difference, but I don't know whether the flanges should be solid or have some play as they are only attached with a roll pin. (The flanges and pins are new if that matters)

Thanks for your input.

[Nicholas R]

Axle flange movement is a difficult measure of whether anything is loose because they're not directly connected to the bearings. That movement is not something that should ever really change because all it is is the backlash in the gears inside the differential. The bearings are actually on the differential crown gear and the differential housing, not on the axle shafts. The movement is just whatever play there is between the shaft gear and the spider gears. In my experience, some play is normal.

This image explains what I'm trying to say a lot better:
http://store.delorean.com/images/Category/large/4-1-3.gif

[DMC-81]

Axle flange movement is a difficult measure of whether anything is loose because they're not directly connected to the bearings. That movement is not something that should ever really change because all it is is the backlash in the gears inside the differential. The bearings are actually on the differential crown gear and the differential housing, not on the axle shafts. The movement is just whatever play there is between the shaft gear and the spider gears. In my experience, some play is normal.

This image explains what I'm trying to say a lot better:
http://store.delorean.com/images/Category/large/4-1-3.gif

Thanks Nick. That makes a lot of sense.

Well, I test drove it again with the nut tightened approximately 1/8 turn from where it was originally.... The result was no real change. My thinking is if the bearing preload was off, the noise should change as you make adjustments.. Correct?

Here is more detail on what the symptoms are:

1) I verified that the noise is not happening in 1st gear, either under load, decelerating, coasting in gear, or when the clutch is engaged or released.

2) There is a slight clicking in neutral, no matter when the clutch is engaged or released.

3) The noise happens loudest in 2nd gear, only when decelerating or coasting in gear. It doesn't matter when the clutch is engaged or released.

4) As mentioned the same thing happens in 3, 4, and 5 to a gradually diminished degree.

I'm afraid the gearbox needs to come out again but beforehand, I am trying to pinpoint as much as possible what to look at because the first time, I corrected the visible damage and all seals were replaced, plus everything else looked great.

Question: would damaged spider gears cause the noise? I couldn't really inspect them inside the differential housing.

Or how about worn bearings on the 2 shafts? (With only 27k on the clock, I wouldn't expect that.)

[David T]

There is no good way to check bearing preload except the procedure in the Workshop Manual. If it was ever improperly set you could have damaged the carrier (dif) bearings so no amount of adjustment will stop a noise. Make sure you have the proper amount and the correct type of gear oil. The spider gears have no effect unless you are turning or a wheel is spinning faster or slower than the other. Worn bearings is a possibility but unless the box was operated without oil it is a rarity.

[DMC-81]

There is no good way to check bearing preload except the procedure in the Workshop Manual. If it was ever improperly set you could have damaged the carrier (dif) bearings so no amount of adjustment will stop a noise. Make sure you have the proper amount and the correct type of gear oil. The spider gears have no effect unless you are turning or a wheel is spinning faster or slower than the other. Worn bearings is a possibility but unless the box was operated without oil it is a rarity.

Thanks David. When I remove it again I'll check it using the procedure in the manual.

--------------------

I tested it again this morning to check linkage ( i.e. Does moving the shift selector cause any change in the deceleration noise). It didn't.

However, I focused on 3rd and 4th gears again today, and I really don't hear the same noise in those gears. I think the faint noise I'm hearing is residual noise from whatever gear is messed up, like I'm hearing in neutral. Therefore, I don't suspect the bearing preload or the spider gears anymore.

So, the noise is really focused on 2nd gear. Which makes sense because when the nut-backing-off event happened in November, I tried to get it in gear after stopping at an intersection, I wouldn't go into first, but it went violently into 2nd. That's where the shift selector damage happened, but perhaps something also happened to the 2nd gear assembly. Something internal as the gears looked normal and I didn't take the gears apart, and the 1-2 selector fork appeared straight.

What would be the symptom of the 2nd gear synchro spring (103106 (http://store.delorean.com/p-8548-synchronising-spring.aspx)) being broken or damaged?

[DMC5180]

Dana ,

There are Half moon needle bearings between each synchromesh gear and shaft the spin on. Perhaps something migrated in there. Also remember the secondary shaft assembly is submerged in gear oil. Lots of churning going on.

http://store.delorean.com/c-288-4-1-2-gears.aspx


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[DMC-81]

I thought I'd update this thread. I took the transmission out again and split the case. Since I wasn't in any hurry to meet a show deadline, I took my time and did everything that I didn't have time to do in the first round, and to check for the cause of the gear clicking.

First up was double checking for clearance on the 1-2 shift fork roll pins, and ensuring the fork is straight.

52726

Everything checked out.

Next was re-examining the gears for any wear, damage, and to ensure they spin freely. Many thanks to Rob Grady who helped me spot anything away remotely, and especially to Nick R. who physically looked at each component for me.

52727

Again, everything checked out.

Next was setting the differential bearing preload. For this I purchased a used force gauge online. I set it at 1 pound of force, which is very slightly tighter than "free spinning", or just tight, then backing off a little.

52728 52729

Later on, I noticed that the nose bearing seemed to move too much axially, so I decided to replace it with an OEM DMC bearing, I also got a Nachi pilot bearing from Rob Grady. Note that these two bearings are different sizes.

52730

Nick helped me remove and replace the nose bearing.... OK, he did the whole thing... :)
52731

While I was there, I was fortunate enough to able to buy a bulletproof coupler from him as he had an extra. :yesss:
52732
Thanks again Nick.

I used Rob Grady's idea of a 50/50 mixture of grease and anti-seize in the coupler and on the shaft...
52733

Installed:
52734

This part tightened up the slight play in the input shaft and will make the transmission better able to withstand future power upgrades.

To be continued...

[David T]

From your first picture look at the roll pin next to the spring on the shifter rail. It looks bent. Replace it and get a small one to put inside it to beef it up. That is the infamous roll pin that breaks when the clutch doesn't work right and you force shifts.

[DMC-81]

From your first picture look at the roll pin next to the spring on the shifter rail. It looks bent. Replace it and get a small one to put inside it to beef it up. That is the infamous roll pin that breaks when the clutch doesn't work right and you force shifts.

Thanks David. It is the picture angle. Actually those 3 roll pins are brand new. The first two from the left are reinforced with a second smaller pin in the middle. I got these from Rob Grady and I detailed their replacement earlier in the thread. This time I was just double checking my work on clearances.

[Drive Stainless]

Thanks David. It is the picture angle. Actually those 3 roll pins are brand new. The first two from the left are reinforced with a second smaller pin in the middle. I got these from Rob Grady and I detailed their replacement earlier in the thread. This time I was just double checking my work on clearances.

Ask David how many transmissions he's rebuilt. :umm:

[opethmike]

Ask David how many transmissions he's rebuilt. :umm:

You'll get some great information on checking your tire pressures, and to consult the workshop manual for the maintenance schedule.

[DMC-81]

Continued..

This time, I decided to tackle the replacement of the seals in the gear selector. One needs to remove the plug at the top of the cover to tap out the 2 roll pins to disassemble the selector assembly.

52738

All apart. I cleaned the parts and changed the bellows and seal.
52739

Back together:
5274052741

I also opted to have my flywheel and the new Valeo clutch pressure plate balanced by a local Speed Shop. The red mark indicates the optional indexing to ensure that it is installed in the same orientation that the unit was balanced.
52742

I also took extra time to clean the rear of the engine:

52743

Time to put the transmission back together (again):
52744 52746 52747

Queued for installation at DMCFL..
52748

To be concluded....

[David T]

I only looked at the picture and it looked to me like the pin was bent and I could not tell that you had installed the smaller ones into the larger ones. If, as you say, the pins are not bent, were replaced, and beefed up, you should be good to go. As for how many transmissions have I rebuilt, I do not keep track, it is dozens. Automatic and manual, cars, trucks, construction equipment, motorcycles, and a helicopter. But you do not have to go by my advice if you are in contact with Rob G. Make sure you get the nuts on the ends of the shafts really tight and staked so they can't loosen up. Locktite would also be good.

[DMC-81]

I only looked at the picture and it looked to me like the pin was bent and I could not tell that you had installed the smaller ones into the larger ones. If, as you say, the pins are not bent, were replaced, and beefed up, you should be good to go. As for how many transmissions have I rebuilt, I do not keep track, it is dozens. Automatic and manual, cars, trucks, construction equipment, motorcycles, and a helicopter. But you do not have to go by my advice if you are in contact with Rob G. Make sure you get the nuts on the ends of the shafts really tight and staked so they can't loosen up. Locktite would also be good.

No worries David. It's a long thread..

[DMC-81]

The great team at DMCFL tackled the transmission install...

Flywheel and crossover pipe:
52768

Clutch and pressure plate:
52769

Transmission etc.:
52770

They did a cross gate cable adjustment and now it's better than ever.
52771

Done:
52772

The results:

1) It shifts positively in all gears.

2) The clutch action is smooth and strong.

3) The clutch pedal action is fairly light and quiet.

4) The engine revs very smoothly. ( I'm glad I had the balancing done for good measure)

After 2 days of shakedown driving, I'm happy.

I'd like to thank everyone that helped me through this frustrating problem. But in the end, it forced me to refurbish my driveline, and I wound up with a transmission with flaws/weaknesses corrected.

Here's my advice to everyone driving a manual: If you ever start to hear gear whine, (especially in 3rd and 4th gears) on deceleration/ coasting, that's more than likely a sign of the shaft nut beginning to back off. You need to drain the gear oil, take the back cover off the transmission and inspect/ deal with the nut. That's much easier and less expensive to do before the damage inevitably happens.

[Morpheus]

I'm glad we could help you get everything back together!

[DMC5180]

Okay, Now that you're finished, lets see some photos of Bugs splattered on the front bumper. [emoji4]

[Nicholas R]

This is great news Dana! Can't wait to see you at all the local shows now! It will be nice to loose to you for a change instead of loosing to Brandon :wink:

[Morpheus]

This is great news Dana! Can't wait to see you at all the local shows now! It will be nice to loose to you for a change instead of loosing to Brandon :wink:

That was a total fluke! Way more people were ogling (and appreciating) your car than mine that day, I figured you would be a shoe-in for the win. 8)

[DMC-81]

I'm glad we could help you get everything back together!

Thanks! Your team did a fine job. :fancy:


Okay, Now that you're finished, lets see some photos of Bugs splattered on the front bumper. [emoji4]

Ha! Yes definitely. Funny thing is, the first thing I do when I get home from a highway trip in any car is to wipe the front bumper good with a wet microfiber cloth. Around here, we have love bugs which can ruin your paint if left on.



This is great news Dana! Can't wait to see you at all the local shows now! It will be nice to loose to you for a change instead of loosing to Brandon :wink:

Thanks! I'll plan to be there. I like to park near your car to see all the people doing this... :jawdrop:

[DMC-81]

After driving the car around 100 miles last fall, I noticed a slight bearing noise and a secondary noise problem that got progressively worse: a loud rattling predominantly in 2nd gear when accelerating lightly.....it sounded something like "Rat-a-tat-a-tat". It seemed as though the gearbox was self-destructing. Although quieter, I also heard the noise in 3rd and 4th gears.

So, as much as I didn't want it to be the case, the gearbox had to be removed again for round four of assessment and repair. It was said on this forum that these cars can sometimes make you hate them. This was the first time for me.....

I had great initial conversations with Rob Grady and DMCFL, and they pointed to bearings and linkage. After giving myself a break from the car over the holidays, I decided to remove the gearbox myself using a low profile transmission jack:

http://dmctalk.org/attachment.php?attachmentid=55710&d=1521681503

The low profile jack can be used with the car on 4 jack stands with a medium height setting. After getting the gearbox off the jack and on the floor, I removed the passenger rear wheel, jacked this corner of the car a few more inches, tilted the box and slid it out. This was relatively easy:

http://dmctalk.org/attachment.php?attachmentid=55711&d=1521681616


Upon disassembly, I saw that my carrier bearings were scored, both the races and the rollers. I'll change these.

http://dmctalk.org/attachment.php?attachmentid=55712&d=1521681707

Plus, the thrust bearing on the secondary/output shaft is also slightly scored. This will also be changed:
http://dmctalk.org/attachment.php?attachmentid=55713&d=1521681826

to be continued...

[DMC-81]

My theory on the bearing wear is that little pieces of shrapnel from the broken spring and or metal flakes from the gear wear during the brief period of the nut backing off caused this scoring on the bottom half of the box where the gear oil was, and the wear manifested itself after a few miles. So, I disassembled the secondary shaft as much as possible to look for more wear. Here are the parts of the secondary shaft from the lock nut to the outer half of the 1/2 hub (103108 ):
http://dmctalk.org/attachment.php?attachmentid=55717&d=1521682201

Here are the second gear needle bearings. Because there was a violent jar when I tried 2nd when the nut initially backed off, I will replace these bearings even though they and everything else look great. Now I'm satisfied that the 2nd gear rattling noise is probably in the linkage, not in the gear itself, and that I didn't have shrapnel damage in the bearing area.
http://dmctalk.org/attachment.php?attachmentid=55719&d=1521682357

Here is the secondary shaft disassembled as far as it can be. Because 3rd and 4th gears were shrunk on during manufacture, they can't be removed nor the pinion bearing:
http://dmctalk.org/attachment.php?attachmentid=55720&d=1521682415

As before, the ring and pinion look normal. That's a good thing, as I learned that these were lapped together during manufacture so they have to be replaced as a pair:
http://dmctalk.org/attachment.php?attachmentid=55721&d=1521682467

I stopped by Nick Roedl's place to borrow the adjustment nut tool again and I was fortunate enough to have he and his Dad help me remove the carrier bearings from the differential. That was very helpful:
http://dmctalk.org/attachment.php?attachmentid=55722&d=1521682693
Thanks Nick!

Using Nick's advice, I removed the outer carrier bearing race from the case half using a seal puller. I also used a disc from a bearing driver set to protect my new axle seal and surrounding area. The trick here is to take your time, don't force it, and avoid getting the race crooked:
http://dmctalk.org/attachment.php?attachmentid=55724&d=1521683013

To install the new carrier bearing outer race, I first lubricated the area and the race, then I used a bearing driver tool to tap it in. As was the case in removal, the key is to avoid getting it crooked:
http://dmctalk.org/attachment.php?attachmentid=55727&d=1521683223

to be continued..

[Nicholas R]

Happy to help Dana! I really hope this is the end of this saga.

On a side not, just something to maybe keep in the back of your mind, I actually recently had a similar sound occur. I immediately thought of you when I started hearing it. When I was sitting in the car and driving, I would have bet money that the sound was coming from the transmission. Being that I heard the sound in most of the gears (consistent with vehicle speed), I figured it had to be output shaft or differential related because the output shaft is always spinning consistent with wheel speed rather than engine speed. I got the car on the lift with both wheels off the ground and in various combinations of transmission in gear, transmission in neutral, one wheel chalked, both free, etc, I would spin one of the rear wheels as fast as I could. Sure enough, spinning the passenger side wheel only, I heard the sound. I had another person stand under the car while I spun it to tell me if the sound was coming from inside the transmission or one of the CV joints. To my surprise, they said they were positive it was coming from the wheel hub area.

As it turned out, the sound was coming from one of my brake pads. The pins holding my brake pads in place on my passenger side rear were very worn and necked down in the areas where they supported the brake pads, and the hole in the pads themselves were wallowed out. Best I can guess, the brake pad would either lift up and then drop as the brake disc went around. I'm guessing that the disc itself is a tiny bit warped such that with every rotation, it would skim the pad, pick it up and drop it (or at least bounce it around). Just something to consider. Either way, I hope the tapping is soon to disappear!

[David T]

How many miles is there on the gearbox? The bearings don't look scored so much as heavy wear which is normal. If foreign objects got into the bearings they would look MUCH worse. The wear on the differential races can be explained by an improper adjustment more than anything else.

[DMC-81]

Happy to help Dana! I really hope this is the end of this saga.
Snip
As it turned out, the sound was coming from one of my brake pads.
Snip
Just something to consider. Either way, I hope the tapping is soon to disappear!

Thanks Nick! Me too! I'll check them out.


How many miles is there on the gearbox? The bearings don't look scored so much as heavy wear which is normal. If foreign objects got into the bearings they would look MUCH worse. The wear on the differential races can be explained by an improper adjustment more than anything else.

Thanks David. There are 27K miles on it. You probably can't see it from the picture but running your fingernail in the race shows that it is actually scored. The thrust bearing as well, although less so. I wouldn't expect heavy wear at 27K, and because both carrier and thrust bearings were scored, it led me to the debris theory, even though it wasn't run long under those conditions. I was pretty particular about the adjustment last time (in post 73), but who knows.

----------------------------------
New bearings:

I had a nearby Mercedes/Porsche repair shop press the new races on the differential (and the 1 / 2 slider hub). There was one shim on the opposite side of the bolt side that's pictured that I needed to ensure was put back:
http://dmctalk.org/attachment.php?attachmentid=55728&d=1521683298

With the new bearings in place, it was time to set the pre-load. The specification for new bearings is 3 to 7 pounds of force measured on a force gauge. I set mine at the lower end... 3 pounds :
http://dmctalk.org/attachment.php?attachmentid=55730&d=1521683471

I used the correct tool borrowed from Nick to adjust the pre-load:
http://dmctalk.org/attachment.php?attachmentid=55729&d=1521683403

Set and locked (I used a new o-ring):
http://dmctalk.org/attachment.php?attachmentid=55731&d=1521683546

Thrust Bearing:
I installed a new SNR thrust bearing ( FC 10893 ) on the secondary shaft. This doesn't have to be pressed on. It included a new spacer that goes between the races. The old one is on the table and the new one is installed:
http://dmctalk.org/attachment.php?attachmentid=55732&d=1521683636

Breather:
In this round, I finally found a new gearbox Breather (103047) at DeLoreanGo. For a flexible plastic piece, this looked pristine and pliable. Mine was cracked and mostly missing. Trial fitted:
http://dmctalk.org/attachment.php?attachmentid=55735&d=1521684325
Installed:
http://dmctalk.org/attachment.php?attachmentid=55736&d=1521684394

[Rich_NYS]

Hate that you had an issue, but I love looking at your projects & pics!

Fingers crossed for trouble-free miles, brah!

[DMC-81]

Hate that you had an issue, but I love looking at your projects & pics!

Fingers crossed for trouble-free miles, brah!

Thanks Rich!

-----------------------

Assembly: (selected steps...more details are in the Manual Transmission Repair & Restoration " album on my profile)

I meticulously cleaned the case halves after the races were installed, including removing the bearing retainer and anaerobic sealant residue and cleaning/ chasing the threads for both end covers:
http://dmctalk.org/attachment.php?attachmentid=55733&d=1521683698

I trial fitted the gears before bearing retainer is applied and re-assembled. Everything looked great and was clean and tight:
http://dmctalk.org/attachment.php?attachmentid=55734&d=1521683754

After assembling the case halves and installing the 2 locknuts with red Loctite , it was time to put the covers on. I used new NOS paper gaskets from P.J. Grady. I found that these ones don't shrink/distort when the Indian Head gasket shellac that I used is applied.
http://dmctalk.org/attachment.php?attachmentid=55750&d=1521763708

As before, I used blue Loctite on the M10 bolts for the clutch housing and made sure the threads were cleaned to get an accurate torque reading:
http://dmctalk.org/attachment.php?attachmentid=55749&d=1521763620

Bearings replaced and the transmission is ready to go back in the car...again!:
http://dmctalk.org/attachment.php?attachmentid=55753&d=1521764117

I refreshed the grease/anti-seize mix to the input shaft/ throw bearing area:
http://dmctalk.org/attachment.php?attachmentid=55794&d=1522254701

Mated to the engine and installed. I temporarily used four M10 x 80mm bolts as Dennis suggested in post 19 to help align things which was VERY helpful:
http://dmctalk.org/attachment.php?attachmentid=55798&d=1522255258

Here is a view of my transmission tag. It was only serial number 000086 after DMC switched to the 369-08 type of UN-1 which, I suppose explains why I had the rare nut backing off flaw.... Mon Dieu!! Also, "boîte pont" or literally "box bridge", is French for gearbox/transaxle:
http://dmctalk.org/attachment.php?attachmentid=55754&d=1521764190

On to linkage...

[David T]

Looking good! I don't have a whiz-bang digital scale, I use an old spring scale, but whatever works. If you did feel something on the bearing races you are correct in trashing them, it wasn't visible in the picture. Unusual for them to be trashed at 27K miles so something out-of-the-ordinary went wrong. Was the box ever run dry? Did anyone every have to add a lot of gear oil because of a leak? When you drained the box was there anything in the oil? Did you find any fragments when you disassembled and cleaned the parts?

[DMC-81]

Looking good! I don't have a whiz-bang digital scale, I use an old spring scale, but whatever works. If you did feel something on the bearing races you are correct in trashing them, it wasn't visible in the picture. Unusual for them to be trashed at 27K miles so something out-of-the-ordinary went wrong. Was the box ever run dry? Did anyone every have to add a lot of gear oil because of a leak? When you drained the box was there anything in the oil? Did you find any fragments when you disassembled and cleaned the parts?

Thanks! I doubt the box was run dry. Before my ownership, it was well cared for by the original owner. But, when the event happened, and I drained the oil, it had some small metal flakes in it. When I disassembled it the first time, it had some pieces of the broken spring caught up in the gears, and stuck to the magnet (see post 44). So, that's why I'm thinking about the debris cause. Since then, the oil has been changed 3 times, so the box is well flushed.

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Linkage

Rob Grady felt that my 2nd gear rattling noise was likely in the Bellcrank assembly. He said that he's seen more than a few make that noise as the original pivot bolt gets loose as described in this thread:
http://dmctalk.org/showthread.php?13255-Pivot-Bolt-Depth&highlight=Pivot+bolt+depth

Indeed, there is also a Service Bulletin on it, ST-19-10/81 Gearshift Action

This made total sense to me. I remembered that my rattling noise only happened when I was accelerating lightly, and I heard it in multiple gears. I supposed a hard acceleration would tighten up the linkage and therefore it would not make the noise. Plus, if the pivot bolt /Bellcrank was the source of the noise, it would be magnified/radiated throughout the frame based on where it was. That would explain why it seemed that the transmission was self-destructing below me.

I looked at my Bellcrank and sure enough, it was loose. There was also excessive play laterally between it and the pivot bolt. There is a brass bushing in it that may be slightly worn in addition to the pivot bolt. Noise problems aside, I didn't want to get stuck with a sheared or missing pivot bolt.

So, to address the issue, I chose to replace the Bellcrank assembly (100549), and get the improved grade 12.9 Shift Pivot Bolt & Hardware ( 105844GA ) from PJ Grady that was discussed in the above thread. Here are the new parts:
http://dmctalk.org/attachment.php?attachmentid=55742&d=1521686172
(Note: the pivot bolt washers are out of sequence in this picture)

Here is the new Bellcrank and improved pivot bolt installed with a 50/50 mix of grease and antisieze between the bolt and the crank. I applied red Loctite to the jam nut. I learned from Rob Grady that my strip of missing epoxy paint was intentional. The factory workers put on a strip of tape before painting the frame and removed it after the paint was done to avoid extra material that would interfere with the Bellcrank operation. The rust protection applied to the strip was grease. So after cleaning off the old grease, I liberally applied my 50/50 mixture to the strip as well. Now the Bellcrank is tight but free moving.
http://dmctalk.org/attachment.php?attachmentid=55758&d=1521806394

I also removed the gear change assembly and front gear change tube to clean, lube, and install the DMC bushing kit:
http://dmctalk.org/attachment.php?attachmentid=55738&d=1521684891
I also cleaned the mounting area:
http://dmctalk.org/attachment.php?attachmentid=55740&d=1521685076

Finishing up....

I finished re-installing the rest of the shift linkage with all new bushings, and I had to do a cross-gate cable adjustment again:
http://dmctalk.org/attachment.php?attachmentid=55821&d=1522655707

I added a DMC M/T Noise Isolator (108903) as this was a running change after my early car was produced:
http://dmctalk.org/attachment.php?attachmentid=55822&d=1522655831

I also replaced my tired and torn Shift Boot with DMC's improved version ( 100688 ) with the metal bracket. I noticed that it snapped on tightly..nice! I finally aligned and tightened my OEM shift ball:
http://dmctalk.org/attachment.php?attachmentid=55823&d=1522655985

The gear change action seems tight and smooth! Ready to test drive...

[dn010]

The bushing kit is one of the best things I did to my car, it removed so much slop/play in the shift linkage, it was a night/day difference when I did it.

Looking very good, hopefully you'll have a very uneventful future and can enjoy driving instead of repairing!

[DMC-81]

The bushing kit is one of the best things I did to my car, it removed so much slop/play in the shift linkage, it was a night/day difference when I did it.

Looking very good, hopefully you'll have a very uneventful future and can enjoy driving instead of repairing!

Thanks Dan!

------------------------

Well, I drove the car over a few days and the results are excellent. The car shifts as smooth as butter with an extra tightness in the linkage and there is no noise at all at any speed or acceleration scenario. It has only been a few miles, but I'm cautiously optimistic.

I have also noticed that the noise isolator did make a difference in the cabin noise levels. It's actually quieter. And just like that, I love the car again.

I'd like to sincerely thank everyone again who helped me through this problem. It really took a collection of several experienced people to help me sort through the impacts of this rare problem. Through several vendors, I got the parts for a completely refurbished and strengthened transmission.

I hope this thread is helpful to other owners either in fixing the flaws/weaknesses or in general refurbishment.

I'll repeat my advice to the community:

If you ever start to hear gear whine, (especially in 3rd and 4th gears) on deceleration/ coasting, that's more than likely a sign of the shaft nut beginning to back off. If so, I strongly recommend you immediately park the car, drain the gear oil, take the back cover off the transmission and inspect/ deal with the nut(s). That's much easier and less expensive to do before the damage inevitably happens...trust me on that. :)

Even better: If you have or acquire an early car, especially one with a fairly low serial number on the transmission I would strongly recommend doing the above service proactively.

Let my pain be to your benefit.

Cheers,