VWaddict

The sight 'shissssshhh' noise when you lift off ('engine braking') is normal, I presume? -Mine's always done it, so I've just assumed that it's normal... mind you , I'd feel pretty stupid if it's a sign of impending DOOM or anything!

Oddjob

Not the LSD, maybe pinion bearings unloading.

User 52121

Can't say my car makes any kind of noise like that, unless you're referring to the faint "pshhh" sound that is the bypass valve opening?

Scott H

Take both rear wheels off and try spinning the axle and see if there is any audible noises. The noise you describe is more associated with failing bearings than an LSD. What fluid are you running and when was it last changed?

VWaddict

Jim, it's not the engine making the noise, it's definitely later on down the drivetrain. -Doesn't do it if the clutch is in... only on engine braking.

Scott, I haven't heard anything nasty. -I spun the wheels when it was up on the lift at Zotz last week, but didn't hear anything (I was looking for an elusive 'squeak' which actually turned out to be the spare tire shifting when going over bumps... -oops! )

The tranmission fluid is Swepco 201, and was changed about 20,000 miles ago. -I have a gallon of it, not sure when it'll need to be changed now that I think of it.

Now that I'm on a quest to quieten the whole of the rear end down, I'm focusing on every little noise I hear... -I have a 'clunk' which seems to be coming from a rear shock absorber, a 'clack' which I'm pretty sure is the rear hatch pins, and when I had an 'eek-a-eek-a' which was the spare wheel shifting, and some swaybar bushing noises, it was really irritating...

-Every time I drove down a road which wasn't as perfectly smooth as a pool table, it sounded like I had an over-caffeinated Latin percussion section rehearsing in the trunk!

ausgeflippt951

How many miles are on the trans? Also, more important question: do you have a lightweight flywheel/pp?

I hear the same sound when I unload; my tranny's got ~115k on it. I could never hear the sound until I installed the Fidanza and KEP fw/pp. In my case, it has to do with the resonance frequency of the rotating components. When the FW/PP were heavier, there was enough damping in the components that you couldn't hear the noise as readily.

I've been hearing that sound from a number of different cars for years and it doesn't seem to be a problem.

Euro951

Pinion bearing going south.... it will get louder

RobE952

I too have a lot of loud "gear" noise on decel. It started (or rather I started hearing it) when I changed to a urethane trany mount last year.

2 weeks ago my trany let go on the track. Related? Probably. Although my mechanic says all the bearings, except the one at the rear of the casing which exploded, look good.

VWaddict

Interesting... I don't have a lightweight flywheel; -just stock... though the clutch is the fourth one over the many years & miles, I think. The tranny has almost 250,000 on it, but they've been using Swepco 201 since the first change, which was at 20,000 miles... However, it occurs to me that this has an S2 Ring & Pinion, so I wonder if that's part of the noise source?

Sorry to hear about your tranny-grenade.. YIKES!

I understand that the tranny mounts are also urethane on this car too. -I'd have to dig though the 'library' of service history to be 100% certain though.

So, most of the suggestions seem to be gravitating towards the pinion/pinion bearings. -Since this is the S2 ring & pinion, I wonder if it's been like that since it was fitted, and it's just so audible because it's mounted with harder mounts?

I don't think it's got any more audible in the ~30,000 miles since I bought the car, but now that I'm concentrating on rear end noises, I thought I should ask.

I wonder if I could take it to the guy who installed the ring & pinion and see what he says.

-Keith

944hal

My Turbo track car has LSD and has a bit of a whine on deceleration. Probably magnified by the fact the car has no insulation. I bought the LSD tranny with only 10K on a rebuild. Hope they did a good job ) Oh, also have a KEP lightweight Pressure Plate, but stock flywheel.

Tom M'Guinn

I've had three transaxles in my car, and everyone of them has made a gear-noise on decel -- one non-LSD and two LSD's. My original non-LSD made that noise for the full 40k I had it in my car, until it finally blew up in 2nd gear. I attribute the failure to the 500+/- HP I was pushing through it at the time, rather than the noise. My current one is a fresh rebuild from Kevin Gross, and it still makes the noise. He said most of them make a noise, even in good shape, though offered to take a look at it when I next remove it. I've heard some folks say it is actually the clutch or torque tube, but I've also changed both of those with no difference in the sound. The only thing left unchanged in my car are the axles and wheel bearings...

odb812

I noticed the same noise with mine and started a thread to see if there was a problem. I got pretty much the same response: probably nothing to worry about.

https://rennlist.com/forums/944-turb...n-bearing.html