G50 mechanic in So. Cal (oh I got problems...)
 

Oh I got problems, with a capital P and the rhymes with T and that stands for transmission :(

My 89 930 with 41k miles has a lot of slack in the driveline, clunks when shifting (although shifts smoothly), and I need help...

Here's what I've checked: CVs (good), tranny/engine mounts (good), other play between wheels and tranny (none).

Changed to Mobil 1 gear oil 4000 miles ago. I was concerned so changed again to check quality of the oil 1000 miles ago (at next engine oil change). It was clean, and drain magnet showed almost perfectly clean (the usual little 'dusting' of particles). No metal in the gear oil.

Not a lot of time to work on the p-car right now but jacked up one side. Tranny in first, I can rotate the elevated side wheel approx. 15 degrees from side to side, with little effort I can make a clunk. There is noise in the tranny, sounds/feels maybe like somewhere in the differential but I can't tell for sure (it is the factory ltd. slip). Seems to drag in the tranny a little bit/gear noise. I can rock the car a couple of INCHES when 1st is engaged. WTF could this be?

The other significant problem here is that I have no tranny experience (who knows why, I've done every other type of part on cars including p-car engine rebuilds) and I've only got the turbo factory manuals and the bentley which gives me NO G50 information. The Carrera manuals are coming but not soon enough!

Long and short of it? What could it be, what can I easily check in my very limited time and I suppose at this point, does anyone know of a GREAT G50 mech. either in the upper S. Cal area (I'm in Ventura, CA) or who can arrange shipping? I'll pull the motor/tranny myself and either take it in or ship it (local is better as I can take the car by before tearing it apart).

Even better than all that is someone to come up with something I can do in 10 hrs. or less to fix the thing!

Thanks to all once again!

I spun the main pinion bearing in my 87's G50 and it did pretty much the same thing. Lots freeplay in the drive train. Everyone told me it couldn't be the transaxle and we never found a reason why.

The one name that I have been recommended is in Orange county which is a bit of a hike for you. It is Vince at Aussco (714)758-8500. He comes highly recommended by a friend who is technically very sharp and has had 915s and now G50s done for him.


Wayne

Todd: Call Klaus Holthaus at NARW in Reseda. He's realtively close to you, and knows the 911 like the back of his hand. If you want to drive a bit further, call Dave at TRE Motorsports in North Hollywood. Both should be able to help you.

You want to call Tony Gerace at TLG Porsche Service. He's in North Hollywood. He's the best there is.

Hmm...i dunno about G50 but 930 factory manual says "GL-5 lube", and i doubt Mobil 1 is GL-5 speced. Also, there is special additive to be used in LSD-equipped tranny's.

About moving wheels back and forth 15 deg. , that's normal. I would check CV's toroghly (as you did) and then start troubleshooting the rest. If you hear "bucking" while driving ~1000RPM at low speed, it's probably CV's.

41kmiles is nothing! I had 157kmiles on my 930 tranny with slightly worn 3-rd synch.

Thanks for all the recomendations! Spun pilot bearing, hmmm...

As far as the Mobil 1, this is from the data sheet:

Mobil 1 Synthetic Gear Lubricant is suitable for all automotive applications where lubricants meeting API Service GL-5, are recommended.

It also contains limited slip additives. I don't think it's the problem but you never know...

All I can say is that SOMETHING isn't right.

I'm going to see if I can't break away from work and run out to see a wrench. Of course if I was REALLY smart I would've gotten some opinions from the folks on SB RUN I but of course, I was having way too much fun to THINK!

Thanks gents!

Try Tony Callas at Callas Rennsport...

www.callasrennsport.com

-Wayne

What about the clutch? 13 yrs old, rubber center, no? Didn't think about this until I called Callas Rennsport and T. suggested...

I'll have him check it out today and then we'll see!

Thanks again!

Sorry, i tought you were using ordinary engine Mobile 1 oil...now i read that you stated "gear oil", so oil probably isn't issue...

Well, mystery solved (we think). The experts concur that indeed, the clutch disc is at fault. Somewhere I got it in my head that my car didn't have the rubber centered disc so I ruled it out as not possible. Armed with the info. that it does it makes perfect sense. 13yr old rubber getting use after a fair amount of sitting = not very happy rubber! The play in the drivetrain being taken up in either 1st or reverse, the 'noise' from the diff. area (bellhousing) when rotating one wheel...

The up side to this tale is that I now have a reason to pull the engine and tranny and get all greasy with a friend and some beers. The fiance will be taking pictures of me taking the expensive new car totally apart after less than 4 months of ownership, which of course I will post!

Thanks to all who contributed, to Pelican for the parts and for Tony at Callas Rennsport where I will take my car when I don't have the time to wrench on it myself!

More to come...

Be sure to post a picture of that rubber disc when you get it out.

I know a Turbo has more grunt and heat than a Carrera, but my disc was still quite useable after 14 yrs. and 62k miles. The G50 discs are notably heftier than the notorious SC rubber discs and have been said to not fail nearly as frequently.

I replaced it anyway with an early Turbo spring disc. My car also has a bit of slop in it with the car in gear. Trans. is a little noisy, but still operates nicely.

Here's a shot of the infamous rubber disc if anybody gives a......

http://forums.pelicanparts.com/uploads/P1180093.JPG

http://forums.pelicanparts.com/uploads/P1180094.JPG