Grind to first when warm

[mowpow]

My 5 speed shifts fine for the most part but when it gets warm it sometimes grinds to go to 1st met with some resistance too. All other gears are fine, just first. I see that the PO replaced the line to SS at some point and it looks like the slave clutch was swapped at the same time. Clutch is very firm, bruises my foot in traffic hah. Any thoughts what could cause the first gear problem only when the car is warm?

Thanks,
Jake

[GS450-Junkie]

mine did the same thing last year...I would recommend bleeding the clutch system. Should be done every 2-3 years. Might be air or moisture in the system. Worse case scenario master or slave cylinder is leaking and would need to be replaced. Try bleeding first. Mine was bled, and worked fine. Mine had resistance in first as well as reverse, then would shift through the gears perfectly fine. I'm sure others will chime in..... but that's the first thing that came to my mind.

[Nicholas R]

Any idea what kind of gearbox oil you have?

[DMCMW Dave]

Any idea what kind of gearbox oil you have?

Very important question. It makes more difference than you might imagine. Some of the new "super" transmission oils don't play will with this old thing. It seems happiest with plain old 80W90 non synthetic/non some fancy color gear oil.

[NightFlyer]

Very important question. It makes more difference than you might imagine. Some of the new "super" transmission oils don't play will with this old thing. It seems happiest with plain old 80W90 non synthetic/non some fancy color gear oil.

I'm using regular old Lucas 80W90 from Menards, and haven't had any issues :thumbup:

[DMCMW Dave]

I'm using regular old Lucas 80W90 from Menards, and haven't had any issues :thumbup:

Menards? That's probably lawnmower oil.

[tom kish vin. 4357]

Menards? That's probably lawnmower oil.

That's OK Dave Nightflyers car has a lawnmower motor in it held together with duct tape!!
:cool1:

[NightFlyer]

Menards? That's probably lawnmower oil.

SWEET :cool1:

[NightFlyer]

That's OK Dave Nightflyers car has a lawnmower motor in it held together with duct tape!!
:cool1:

You mean this isn't what a stock PRV looks like??? I guess I always kinda wondered why it said Briggs and Stratton on it...

http://www.northerntool.com/images/product/2000x2000/706/7065_2000x2000.jpg

[mowpow]

Hmm, I am not sure what gearbox oil is in there. Just to be sure I'm clear on this (this is my manual car ever), gearbox oil is for lubricating manual transmission while "transmission fluid" is for auto trans, is that right?

[David T]

Very important question. It makes more difference than you might imagine. Some of the new "super" transmission oils don't play will with this old thing. It seems happiest with plain old 80W90 non synthetic/non some fancy color gear oil.

Almost as important as what kind of oil is the correct level. A low level can cause grinding. If it is very old (or you don't know how old) you should change it. It is also a good idea to go over and recheck the shift linkage adjustments.

[micmak]

First of all before I say anything, I need to declare that I am not an expert on transmissions. So feel free to condemn me if you wish. However, I have the same problem getting into first, if you could call it a "problem". I replaced the old line with a SS line and put in a new slave cylinder and master cylinder, almost two years ago. But in the hot, hot Summer weather it sometimes still crunches just ever so little when getting into first. So I gently pull it back towards second, and then slide it into first and it works beautifully. One of my friends suggested something at DCS about synchromesh gears only being available in 2nd, 3rd, 4th and 5th, but not in 1st. So by pulling the shifter slightly towards 2nd, you were engaging the synchromesh and as a result, first was easily available. I dunno if that makes sense to anyone, but that is what I do it and it works. Thinking back to older manual transmissions that I have had through the years, I remember doing the same procedure out of habit as it always enabled first gear with little or no difficulty and no crunch!

……Mike……

[Nicholas R]

Hmm, I am not sure what gearbox oil is in there. Just to be sure I'm clear on this (this is my manual car ever), gearbox oil is for lubricating manual transmission while "transmission fluid" is for auto trans, is that right?

Yes, the nomenclature can be weird but it depends on the specific situation. ATF is automatic transmission fluid; thats your typical mercon/dextron 1,2,3,4,5,6, etc. Gearbox oil is most common in vehicle differentials/rear axles. Gearbox oil is usually a heavier weight oil that either fluctuates little when hot (ie 80w-90) or doesn't at all (straight 90w). Manual transmissions can really vary depending on manufacturer and design. My first car was a 98 mustang that was a 5 speed, and it actually called for automatic transmission fluid in the manual transmission. Being that the DeLorean's manual is a transaxle setup where the differential is built into the transmission, we typically use the same type of oil as most rear axles.

Like Dave said the typical 80-90 gearbox oils seem to work best. I love synthetic engine oil but still swear by conventional in the gearbox.

1st and 2nd gear in our transmission do not use synchros with dog teeth on them to help mesh. The synchros are just a cone that rides on the floating gear and fits into the sliding gear selector. The type, temperature, and overall condition of your gearbox oil can greatly affect the mesh of your synchro to your sliding gears, because it affects the friction between the mating surfaces. If your synchro is having trouble meshing, it wont slow down the floating gear and input shaft, making it difficult to shift.

Bottom line is, if you're having some shifting issues and you dont know the type or status of the fluid in your manual transmission, just change it out. It's really easy. There is a plug on the bottom to drain it and a plug in the side to fill it.

Here are a few photos of a transmission I have apart right now.

This photo shows the output shaft parts. The floating 1st and 2nd gear, as well as the 1st and 2nd gear selector mechanism ride on the output shaft.
http://i565.photobucket.com/albums/ss94/NicholasRoedl/Transmission%20Photos/32899A66-75CD-4023-B5A5-EA3F3080C901.jpg


This photo shows the difference between the 1st/2nd gear style synchros and the 3rd/4th/5th gear style synchros. The 3,4,&5 style synchros are much more of the traditional "BorgWarner" style with teeth on them to help guide the selector coupler.
http://i565.photobucket.com/albums/ss94/NicholasRoedl/Transmission%20Photos/A3AD73D0-44B1-4CBC-96EB-8ACFC7540D16.jpg

This photo shows the shafts in the casing. The output shaft is the top and the input shaft is the lower. The 1st and 2nd gear floating gears and selector are on the top output shaft on the righthand side.
http://i565.photobucket.com/albums/ss94/NicholasRoedl/Transmission%20Photos/A956358B-8E6C-4822-A4B6-FDEAF001854C.jpg

[DMCMW Dave]

I really need to emphasize the issue with the correct lube. I also really like synthetics, but I had RedLiine in my own trans and got the occasional hot gear clash, and switching back to the cheap stuff it completely went away. I've had a customer or two with the same issue, where the box just didn't like expensive synthetic lube and converting back solved the issues.

Modern manuals typically use ATF, (much "thinner" oil) but it has to be designed for it.

[NightFlyer]

Just so no one is left with the wrong impression, this is what I'm currently running in my 5-speed manual car:

http://shop.advanceautoparts.com/wcsstore/CVWEB/staticproductimage//N3242/detail/7070041_lco_10043_pri_detl.jpg

[David T]

All of the forward gears have syncros including 1st. If you are having a lot of problems shifting and you have ruled out the transmission you may have problems with a dragging clutch, bad pilot bearing, etc. I agree the good old cheap stuff seems to be fine for us but in the Lotus's we are using all kinds of exotic stuff. Some so exotic it is no longer available! Most of us are now up to Redline MT-90. Not ridiculously overpriced and usually available locally. Deloreans don't require it but it can't hurt. If you are still having grinding maybe the nut is coming loose on 5th gear. Worth investigating before you get a lot of damage.

[DMCMW Dave]

Most of us are now up to Redline MT-90. Not ridiculously overpriced and usually available locally. Deloreans don't require it but it can't hurt. If you are still having grinding maybe the nut is coming loose on 5th gear. Worth investigating before you get a lot of damage.

The Redline MT90 / 75W90NS is what caused my issues. I took it out. So I think it can hurt. YMMV. My nuts are fine.

[mowpow]

Cool thanks everyone. I will drain and refil. Looks like 3.7 liters according to the manual which would be about four 32oz bottles, is that right?

[DMCMW Dave]

Cool thanks everyone. I will drain and refil. Looks like 3.7 liters according to the manual which would be about four 32oz bottles, is that right?

Yes. Fill it until it starts running out the filler hole, you'll have about a cup left over.

[penciltester]

Wow, same thing happened to me today. I had been driving for about 15 to 20 minutes and then going into reverse was rough. Then going into first was rough. The guy I bought my car from had just replaced the clutch line, master cylinder, slave cylinder, bled the clutch and bled the breaks. Im hoping it just needs to be bled again. We had to rebleed the breaks, lots of air in the line.

Also, my dad had mentioned how stiff the clutch was when he drove it. This is my first manual so I wouldn't know the difference but is the clutch in these cars "stiff"? If not maybe the PO didn't quite get everything hooked up right.

[DMCMW Dave]

Wow, same thing happened to me today. I had been driving for about 15 to 20 minutes and then going into reverse was rough. Then going into first was rough. The guy I bought my car from had just replaced the clutch line, master cylinder, slave cylinder, bled the clutch and bled the breaks. Im hoping it just needs to be bled again. We had to rebleed the breaks, lots of air in the line.

Also, my dad had mentioned how stiff the clutch was when he drove it. This is my first manual so I wouldn't know the difference but is the clutch in these cars "stiff"? If not maybe the PO didn't quite get everything hooked up right.

A properly operating clutch is stiffer than your typical Honda, but not exactly truck-like. BUT there are some issues. Often a car that's been stored for a very long time will have a very stiff clutch as the pressure plate mechanism has rusted as well as the contact points in the system. Also, the pressure plate was redesigned about 2005 and the new design is somewhat lower effort. So it's likely that replacing the clutch will result in a lower pedal effort, but it's hard to say that it's worth the cost.

I would try bleeding the system again.

[NightFlyer]

A properly operating clutch is stiffer than your typical Honda, but not exactly truck-like. BUT there are some issues. Often a car that's been stored for a very long time will have a very stiff clutch as the pressure plate mechanism has rusted as well as the contact points in the system. Also, the pressure plate was redesigned about 2005 and the new design is somewhat lower effort. So it's likely that replacing the clutch will result in a lower pedal effort, but it's hard to say that it's worth the cost.

I would try bleeding the system again.

Hey Dave,

From what you've seen/experienced/observed, what's the estimated useful life span of a stock/OEM clutch?

[DMCMW Dave]

....., what's the estimated useful life span of a stock/OEM clutch?

I've changed them on cars with 6000 miles and I've heard of them getting over 100K (I'll bet Hollers get over 200K since the car lives on the interstates).

Depends entirely on the driver's style (or lack of it:facepalm:) and how much of the mileage is on the highway. I suspect that in many cases, the DeLorean was the original owner's first manual transmission car.

[NightFlyer]

I've changed them on cars with 6000 miles and I've heard of them getting over 100K (I'll bet Hollers get over 200K since the car lives on the interstates).

Depends entirely on the driver's style (or lack of it:facepalm:) and how much of the mileage is on the highway. I suspect that in many cases, the DeLorean was the original owner's first manual transmission car.

Thanks! :cool1: