924Board.org

Alan · Joined: 01 Jun 2006 Posts: 8 Location: Athens, Georgia

Just bought a really nice '78 924 with an auto tranny. The car has 33K miles (know this to be true/actual mileage--I'm the third owner and have all the records). At idle, (and also when driving) the tranny has a kind of whirr/whine/buzz to it. It shifts fine and very smoothly. There is no vibration or shaking to suggest bent shafts, etc. There are no fluid leaks, etc. Just the noise, which doesn't seem like it should be there. The most obvious thing to me as a possibility is the torque tube bearings. Anyone have similar knowledge or experience with such noises in an autotransmission? Is there any way to test/diagnose whether it is the torque tube bearings beforehand without just replacing them and seeing if the noise disappears?...Thanks,...Alan

Paul · Posted: Mon Jun 19, 2006 1:29 am Post subject:

How loud is the noise?

Does it make the noise when in park?

Have you tried to determine where the noise originates?

Has the tranny fluid been changed in the last decade?
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Ozzie · Posted: Mon Jun 19, 2006 7:42 am Post subject:

Sorry all quiet from mine- got a buzzing from the fuel pump only.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

Alan · Joined: 01 Jun 2006 Posts: 8 Location: Athens, Georgia

Thanks for the messages. Yes-even in Park, the whirr/whine/buzz occurs--basically any time the engine is running. From both inside the car and when looking and listening underneath, it seems to be coming from the rear-half of the car--nothing from the engine compartment seems to be generating this sound. Regarding loudness--it is definitely noticeable...nothing very loud or high-pitched, but noticeable. If it would help, I could try to record it and post it as a .wav file or something.

As far as I can tell from all the maintenance records I received, there as been no recent service on the trans. In 1986, the first owner spent $$$$ to get the trans. and differential rebuilt by the Porsche dealership in OH where the it was purchased.

So, it sounds like at least routine servicing/new fluid on the trans. What about the possiblity of the torque tube bearings?

PORSCHEV · Posted: Mon Jun 19, 2006 9:56 am Post subject:

I would say TT bearings...they are known for getting noisy when worn out.
_________________
1976 924
5 lug conversion, 17'C2 wheels,custom body work,327 vette engine.

1978-#53 "D" track racer.

Paul · Posted: Mon Jun 19, 2006 10:03 am Post subject:

Since it is doing it while the car is in park, drive the rear of the car up on some ramps, block the front tires, and use a piece of heater hose to find exactly where the noise originates.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Alan · Joined: 01 Jun 2006 Posts: 8 Location: Athens, Georgia

Thanks for the responses and ideas. I took the 924 to a mechanic here that knows them fairly well. He said that the noise I noticed was not anything to worry about--no torque tube or transmission problems heard while the car was running. I guess I am just not quite used to the sounds this new-old 924 makes. Never have had the experience of driving a 924 auto-trans, either, before now. I do remember years ago how some of the old GM three-speed powerglide trans. had a little whirr to them. So, since the transmission shifts smoothly and the car runs well, I'm not going to go looking for something to fix that doesn't need it. Again, thanks for the info. and advice--much appreciated and helpful.