Noise from T85 quattro Gearbox

[S Dewitt]

Doug,

It could be a number of things.

Does the sound seem to be linked with a specific gear? IE does it only occur
of your in one or two gears?

If it simply gets lounder with speed it is more than likely either your
center diff bearing or one of your front diff bearings. It could also be in
your rear diff of prop shaft, to test put the car on the lift the run it
through the gears with the center diff opened and the parking brake on (this
won't allow the rear diff to turn).

If the sound gets worse with increase in engine speed, then it is related to
your input shaft, and could be a throw out bearing or input shaft bearing.

If it gets worse when you push in the clutch then it is a throw out bearing
or the pilot bearing.

More than likely it is your diff bearings. Try changing your trans fluid and
see if it helps. If it doesn't then you'll have to pull the trans and
replace the bearings then re-shim the diff. Bearings are fairly cheap (~20
each).
You can replace one bearing while the trans is in the car (the diff cover
bearing) but you'll have to split the case to remove the diff to get to the
other bearing.

I've had some mechanics tell me that you can just use the old diff shims and
get away with replacing the bearings and not have to reshim the diff. I'd be
leary of doing this as you can damage the new bearings if things are too
tight, or if things are too loose you can wear your pinion gears.

Scott DeWitt
Advanced Automotion
817-939-6761
----- Original Message ----- 
From: "Doug Johnson" <Doug.Johnson at Softhome.net>
To: "Q-List" <quattro at www.audifans.com>
Sent: Wednesday, January 26, 2005 6:32 PM
Subject: Noise from T85 quattro Gearbox


> The local VW dealer in Wichita told me the speed-related noise I reported
to
> them is coming from the "transmission," and it needs to be replaced.
>
> Any thoughts on what, in particular, inside the box might make a
> speed-related noise?  It's not a whine or a grinding sound, like I'd
expect
> from a an impending bearing failure.  It actually sounds like wind, or
some
> very light rubbing.
>
> I appreciate any thoughts.
>
> Thank you,
>
> ~ Doug
>
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