Rust/Corrosion on transmission input shaft
#1
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Rust/Corrosion on transmission input shaft
I have a 1995 Carrera 2 with 40,000 miles 6-speed. When shifting from 1-2 or 2-3, I frequently feel a little "click" or sometimes even a slight grind (dog teeth engaging?), although I never shift it fast. This occurs more when I upshift below 4,000 RPM.
Clutch operation is correct, and it releases fully with engagement just above midpoint. I flushed and bled the clutch slave cylinder recently. Pedal operation is perfect.
First start in the morning, when I back the car out of the garage, the clutch engagement is a bit abrupt, as if it is sticking. So, that bit of stickiness is making clutch operation just a tiny bit slow, therefore the little grinding of the dog teeth when shifting.
I discussed this online with Steve Weiner, and he believes that the cause is rust/corrosion on the input shaft, causing the clutch disk to stick slightly. I think his diagnosis is exactly correct.
Has anyone else experienced this problem? If so, I would appreciate hearing what you found and how you corrected it.
Clutch operation is correct, and it releases fully with engagement just above midpoint. I flushed and bled the clutch slave cylinder recently. Pedal operation is perfect.
First start in the morning, when I back the car out of the garage, the clutch engagement is a bit abrupt, as if it is sticking. So, that bit of stickiness is making clutch operation just a tiny bit slow, therefore the little grinding of the dog teeth when shifting.
I discussed this online with Steve Weiner, and he believes that the cause is rust/corrosion on the input shaft, causing the clutch disk to stick slightly. I think his diagnosis is exactly correct.
Has anyone else experienced this problem? If so, I would appreciate hearing what you found and how you corrected it.
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my car does something similar and I believe with the same cause as you might be experiencing. My car wants to lurch forward a little bit when starting it in gear, and of course the clutch pedal depressed. The original owner of my car put a clutch in the car approx. 25K miles ago.
Many shop do install clutch disks dry and quite possibly without spending the time to wire brush the splines on the input shaft.
I guess one possible downside to lubricating these splines is that there is a chance clutch dust can accumulate or mix with the grease causing sticky clutch disks.
Many shop do install clutch disks dry and quite possibly without spending the time to wire brush the splines on the input shaft.
I guess one possible downside to lubricating these splines is that there is a chance clutch dust can accumulate or mix with the grease causing sticky clutch disks.
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Hi Chris,
Steve advised me of the special lubricant for this application, Porsche # 000.043.005.00 called Optimol-Olistamoly.
We aren't too far apart--maybe we could DIY an engine drop to clean/lube the input shaft. I'd be glad to help with yours so I can learn better how to do mine. I'm retired so my "schedule" is pretty flexible.
Good to hear from you--Happy Holidays!
Steve advised me of the special lubricant for this application, Porsche # 000.043.005.00 called Optimol-Olistamoly.
We aren't too far apart--maybe we could DIY an engine drop to clean/lube the input shaft. I'd be glad to help with yours so I can learn better how to do mine. I'm retired so my "schedule" is pretty flexible.
Good to hear from you--Happy Holidays!
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...and Happy Holidays to you as well!!
I'll be dropping my engine here soon as well for a few other bits to install.
I'll be dropping my engine here soon as well for a few other bits to install.
#5
I had corrosion on my input shaft. On my car, when you would press in the clutch to shift gears, the pressure plate would release pressure, but the disc would stay attached to the flywheel, not letting the car come out of the gear you were in. I had to blip the throttle to release the clutch disc.. I DIY'd this about 6-7 yrs ago, and you should be able to look up the old threads, and I think Robin may have some of the pictures up on his website. Basically, you'll take everything apart, wire brush the shaft real well, and then apply the optimol lube. I don't remember it being what Steve says, but it's in the manual (maybe it was olista long life?). Either way you have to get it from a Porsche dealer, and ironically, not all of them have it. Good luck!
#6
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You want to use Olista Longtime 3EP (#000-043-024-00) on the input shaft and use Optimoly MPO on the guide tube but only if you are using a regular DMF otherwise with a LWF you also want to use the 3EP lube on the guide tube. The MPO product was TSB'd after problems started with the 996 models that were delivered dry so most places (non-dealers) just stick with 3EP everywhere because it was never technically spec'ed for the 964/993. Actually I'm not quite sure what dealers are doing now with the 997GT3.
tube photo courtesy of elbeee964
tube photo courtesy of elbeee964
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Easier to remove transmission only?
Is it easier to remove the transmission only, and clean and lube just the input shaft? Or does the center of the clutch disk also need to be cleaned of any rust/corrosion?
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#8
Some people remove only the transmission, but it is hard to line everything back up. I've done this once already, but I would probably remove the trans/engine again as one unit the next time I need to do a clutch.
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It's going to the shop
I decided to let my favorite shop, Precision Motion in Riverside, CA, do this one. It might be easy with a lift, but I'm not in the mood to spend time under the car wrestling with the transmission. I'll try to take some pictures so we can all see what the problem was.
#11
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IMHO, thats a VERY good call,...
Its more than a handful to wrestle the 150+lb 6-speed G50 out of the car without a lift and a very strong friend (or a special transmission jack). Plus, the chance of bending the mainshaft on reinstallation is higher.
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I dropped the car off yesterday, and picked it up this afternoon. While it was apart, I stopped by and took a good look. Very little corrosion or rust on the input shaft, but it was a bit gunked up, and everything was bone dry. Whatever lube had been applied at the factory was long gone. The shop cleaned and inspected everything (including the pressure plate and clutch disk, which looked like new), lubed it all up with the correct Porsche spec magic stuff, and reassembled, all for $475. All is well and working as it should.
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Good result Bobby! Thanks for posting the conclusion.
Here is a typical example of how these input shafts look before cleaning
Here is a typical example of how these input shafts look before cleaning
Last edited by chris walrod; 12-29-2007 at 12:09 AM.