KuHL 951

I know the car will go another 50K without fixing this but just for jollies...Can the input shaft bearings and 2-output shaft bearings be replaced without a complete trans teardown? The synchros are fine, no shifting issues, but drivetrain noise is pretty loud on throttle lift and coasting. It's not a grinding sound, just seems like a worn bearing or two. The rear wheel bearings are not the source of the noise, I've confirmed that. Fluids are fresh (Redline) and CV's are newer on the axles.

Dmitry S.

Sometimes the transmission will make excessive noise when the clutch is failing. Are you on the original clutch? Pull the transaxle bellhousing window while the car is in neutral, and see how much the torque tube shaft turns each way.

Dmitry S.

Oh - noticed this is for your 83. When you replaced the clutch, did you use the spring centered unit?

bigsheldy

Sounds like the same problem I've got. Sounds like a Sac-town tranny get together in order this summer GREAT.

unsigned

I'm pretty sure KuHL just did his clutch. He offered me tons of advice while I was doing mine.

Also, My tranny make a a good bit of 'bearing' noise on gear-in coasting. I just changed to Amsoil synth gear lube, and it reduced the noise by about 20%. Have you changed the fluids recently?

oops, nevermind on the fluids. One would think I didn't read the post.

porsche924

sometimes it is just the 5th 'floating' gear. it is in higher tolerance and then megaphones through the torque tube. is it possible this might just be the problem?

KuHL 951

I found part of the noise source. My son had borrowed the car while I was getting the 325 ready for him. The shift **** had pulled off and he removed the rubber boot under the shifter and the leather boot wasn't attached on the lip. Made a big difference putting them back in. Clutch is new with spring centered disc. The car has always had more drivetrain noise than the 951. I'm still trying to find out if the input and output bearings/seals can be replaced without disturbing the inner workings. Anyone done this before? I'm pretty sure the bearings are pretty worn.

Steve

tifosiman

It's probably not just bearing noise, it is also the ring and pinion gear making a bit of noise due to wear and resultant lash/gap in the way that they mesh together. FWIW, early (82-85) cars always seem to have a little more perceived trans whine than later cars.

To answer your question on the bearings, you need to remove the input and output shaft assemblies from the case to replace the bearings. You can remove them and replace the bearings, then put everything back together, without needing to re-shim everything. However, as stated above, the whine is probably partially due to the r&p so that re-shim and pre-load work would really be in order while you have it all apart.

If you have the Factory Service Manuals, there is a lot of info in there on taking apart the trans and bearing replacement / preload work. Honestly, this isn't a job for the average home mechanic, IMHO, due to the complexity and special tools necessary. Early 944 transaxles are so cheap (right now) it would make more economic sense to just pick up another one to have as a spare and swap it in when the original one finally grenades.

KuHL 951

Tifo-
I now remember you did a trans rebuild a while back but couldn't find the link. You answered my question very well. I understand what you mean about the R & P, the early cars are noiser it seems. I figure that driving with the clutch in limp home mode for all those months didn't do it any favors, that's for sure. If the bearing replacement isn't going to help that much I'll take your advice and wait until I can find a good take out unit. Thanks again for your valueable input.

Mike C.

If you have a hydraulic press handy, a bearing seperator and can make/borrow a few other fixtures for the press, some heavy duty snap ring pliers, you can do it (I did). However, what you can't get away with is replacing the output shaft bearings (the one behind the pinion gear and the other in the cast iron part of the case) without readjusting the shim thickness on both of these bearings to get the proper R&P backlash and bearing pre-load. Bearings have tolerances. Not only that, in order to remove and replace the pinion bearing race, you must heat the case up to around 300 F. Believe me, you might get the race out with force only but you will not get the new one in without heating the case (otherwise, the steel race just shaves the aluminum in the bore as you force it in). Unfortunately, two of the input shaft bearings are in the aluminum case and the same applies. You can replace the 5th gear and the aft input shaft bearing though. Once you have it apart you can inspect the other bearings for obvious damage.

KuHL 951

Thanks-That info just shut the door on me ever doing it at home! I'll stick with repairs I'm familiar with. There's a very good manual trans shop here in Sac that has done 2 non P-car units for me and the results were amazing. He doesn't like doing Porsches though and it reflects in the price of $1K for a rebuild with new synchros, bearings, seals, and a new R & P. Any gearing or shafts above that will just add to the price. I think I can live with noise as the unit still shifts flawlessly up and down.

tifosiman

That's my point about special tools needed. Most people don't have access to a press, so they would need to purchase one. The plates needed for the press are possible to replicate (although it takes a little work/interpolation to get them right). There are also other tools needed, here is the mostly comprehensive list (some are NLA or very difficult to find, mainly a few with VW part#'s):

Tool# Name
_________________________________________
VW 431 or Kukko 20/10 2 arm puller
n/a Various punches
Kukko 15-17 Gr1 Separator (Large)
Kukko 15-17 Gr2 Separator (Small)
n/a Feeler Blade guages
n/a Shop press and standard plates
VW408a Thrust Pad
VW457 Support Rail
VW454 Thrust Pad
VW519 Pipe
VW411 Pressing Drift
VW412 Pressing Pad
VW401 Pressing Plate
VW407 Pressing Drift
VW472 Pressing Tool
VW473 Pressing Tool
P254b Pressing Tool
n/a Hot Plate
n/a Various wrenches, etc.

I wouldn't recommend anyone to do the job without the right tools.


That is damn cheap. You wouldn't be able to purchase the parts for that much, let alone the press and tools to do it. You're basically getting the expertise and labor for free. For that price, if he stands by his work and is good, I would jump on it. There is much more peace of mind to be had with a nicely rebuilt unite verses a used one of unknown quality/pedigree. Honestly, it is doubtfull that there would be any issue with gears or shafts, they are usually in good shape. It's the things you mentioned that are included in the rebuild that are usually toast when you crack open one of these transmissions.

Mike C.

I'm not trying to discourage anyone from trying it mind you. Just trying to give a realisitic assessment of the tools required as a minimum.