5 Speed gearbox flaw repair

[DMC-81]

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

Flywheel and crossover pipe:
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Clutch and pressure plate:
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Transmission etc.:
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They did a cross gate cable adjustment and now it's better than ever.
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Done:
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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.

[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

[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

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.

[DMC-81]

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

Thanks! Your team did a fine job.

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

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

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

[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:



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:




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



Plus, the thrust bearing on the secondary/output shaft is also slightly scored. This will also be changed:


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 ):


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.


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:


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:


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:

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:


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:


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.