Gearbox Noise

DKW · 12:12 AM

Hi all

I have a 1987 2.5 8v 944 which I really enjoy driving but it has an annoying noise coming from the back end!

When I accelerate there is no noise but if I back off and let the car decelerate there is a metalic whining/grinding noise from the back end, If I press the clutch down the noise goes away, but when I let the clutch out it's back again, but it only happns when the car is decelerating!

It happens when the car is cold or hot and in all gears!

I have checked the fluid level and its fine!

Any ideas?

gearhead290 · 06-10-2004, 02:04 PM

Ring gear and pinion isn't set up right. Congrats, it's now cracked, have fun finding another transaxle.

Tishabet · 06-10-2004, 02:11 PM

I vote for CV joints. ring and pinion causes sounds both accelerating and decelerating, in my experience.

bazar01 · bazar01's Garage

I'd say ring and pinion and carrier bearings. Has any work been done on the gearbox? If yes, then gearhead is right.

idontknow · 06-10-2004, 03:14 PM

CV joints usually make more of a clacking noise, I vote ring and pinion

ae1969 · 06-10-2004, 03:20 PM

uhmmm torque tube bearings ...throw out bearing..... or good old ring a and pinion..............

I feel like highjacking this thread......... :

You know.... I have an NA tranny that I am selling and I was wondering ....would it be easier to sell if I just pulled the ring and pinion out? Cheaper shipping etc???? I have an NA tranny weighting ~150lbs that would cost ~100 U.S to ship into the states..... So I was thinking of just pulling the ring and pinion and ebaying the set.... uhmmmmmm any suggestions...

bazar01 · bazar01's Garage

Alex, not everybody can install and set up ring and pinion correctly because of home mechanic's lack of special tools. Just sell the whole gearbox. Is it any good?
I have a spare gearbox that I just recently rebuilt myself but have not tried it yet 'coz I found a turbo gearbox with an oil cooler. Thinking about selling mine too because it is just taking up space.

gearhead290 · 06-10-2004, 08:19 PM

a good transmission shop can install the R&P though. I have a spare tranny in excellent shape but with a blown R&P, how much would you want for the R&P Alex?

mattdavis11 · 10:46 PM

DKW, change the fluid. Other than that, take care of your machine. If you rag it, you'll become a trans destroyer. Mine has had a whine similar to what you have described for 8 plus years. R&P failures are b/c of mistreatment, much like gearhead290 has seen. I know I jinxed myself with that.

adida(r 944) · 06-10-2004, 10:46 PM

after having mine rebuilt and now thinking of it mine has done the same exact noise since a rebuild but only in nutral, 4th, and 5th gear though... so.. is it just a sloppy R&P or may i have something else wrong with mine?

DKW · 06-10-2004, 10:50 PM

Thanks guys!

I have not had the 944 all that long and the noise was there when I got it but the car came cheap enough for it not to be an issue!

I will drop the oil as suggested and look out for anouther tranny!

Many thanks

gearhead290 · 06-11-2004, 09:46 PM

DKW, watch the tranny fluid for filings when you drop it. If there is a lot of filings you probably have a serious problem on your hands.

DKW · 06-12-2004, 10:25 AM

HI again all!

Well I priced up a gearbox at my local Porsche breakers (P H Sportscars) and they quoted £450.00.

But after a long conversation with the mechanic he said he would like to hear the noise for himself so I took the car down this afternoon and within a few minutes he had diagnosed the problem as the Torque Tube needing to be replaced! which they have in stock for £100.00.

So it looks like I have a days work replacing that! But at least it's a lot cheaper than the gearbox!

SlowToady · 03:39 PM

Oh ****.

I have a kinda whinning/laggy noise in 2nd when I let off the gas, but as soon as you give it some gas (or clutch) it's gone. Only happens in 2nd. Fluid is full and new, trans was replaced after it got hashed at Road America. How do I go about figuring out if it's a R&P or T.T. bearing or what?

Man..I REALLY hope it's not the trans...

EDIT:

Actually, I suppose I could drain the tranny, and just hold a magnet in the stream to catch any metal shavings, ey? That would tell me if it's a R&P or not, because if it's setup wrong, it's gonna shave, right?

..P · 06-13-2004, 05:45 PM

If the noise is a simple gear whine, then do a Google for "Amsoil" and check their Series 2000 75W90 gear lube. I used it in a transaxle that had 165,000 miles on it and it helps shifting especially when cold, and it also took out some of the noise. If your tranny is really worn, then start substituting one or two bottles of the thicker gear lube they offer. It might help get you through for a while longer.

I had my 928 transaxle rebuilt and they filled it with Swepco. THe Amsoil made a huge difference in that one too.

regards, P

SlowToady · 06-14-2004, 12:55 PM

Now I'm thinking I'm hearing it in other gears as well, although I might just be paranoid. The transaxle was rebuilt/replaced before I bought it due to a track incident, so I wasn't expecting to have any problems with it. Perhaps it's just the gear lube? I'm going to put either Amsoil or Swepco in there, and see how things turn out.

If the noise I'm hearing isn't the R&P, what else might it be? How do I determine if it's the Torque Tube?

Thanks

SlowToady · 06-17-2004, 10:27 AM

I drained my tranny into a coffee can and check that for metal shavings, and it was perfect. When I stuck my finger in the drain hole there wasn't even any of the ashy soot stuff you'll find when the gears are worn. Filled it back up with 75W90 GL5.

Are the rear CV boots supposed to have grease in them? Because if they are, mine sure don't. I'm thinking that it might be the CVs or wheel bearings and the noise "goes away" when I'm on the gas because of engine/exhaust noise. What else should I check out?

nickd · 06-17-2004, 10:37 AM

Audi transaxles use GL-4. The GL-5 will be hard on your Audi syncros.

-nick

jimbilly · 06-17-2004, 02:11 PM

All 3 Porsches I've had have had some gearbox noise. Not so bad with the carpet in, but kinda noisy with it out. I had a lsd installed in one, and and tranny rebuilt at the same time, -still noisy. Another guy openened it up to re-install the oil cooler, he said the r&p were set up perfect, -still noisy. I think some noise is normal.

SlowToady · 06-17-2004, 04:37 PM

I was under the impression that GL5 was the standard replacement for GL4. As I gathered, the only difference is that the GL4 the 944 calls for is straight 80, whilst what I put it in 75W90 which shouldn't cause too much difference. Anyway, I only put it in to get me home from work, I'm ordering some Amsoil or Swepco.

Does anyone know if using GL-5 is actually harmful to our transaxles?