Rear end noise

[Tom Leppke-Hennig]

Message: 2
Date: Tue, 6 Apr 2010 13:24:26 -0500
From: "Ben" <blament at gmail.com>
Subject: Rear end noise
To: <quattro at audifans.com>
Message-ID: <016c01cad5b6$65159d80$2f40d880$@com>
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I will try to get the car up on a hoist and have a listen, as has been
suggested. The noise is a constant droning or loud humming - sort of like
extremely bad tire whine. There is no change in corners and the noise begins
almost immediately upon leaving from rest. It doesn't seem to change with
speed, either. There is a new wrinkle this morning, however. Upon takeoff
there is a very brief clicking noise. This noise disappears once firmly
underway and it doesn't happen on every take off. ODD!

Peace,
Ben

Ben,

My vote is still a bad bearing on one of the rear wheels. When a bearing
gets bad enough, the howl can be there whether the wheel is loaded or not.
It will howl anytime the wheel is even rotating. This is easy to check.
Get that corner in the air and spin the wheel by hand. If a bearing is bad
enough, you can feel the grumble in your hand as you rotate the wheel. If
the bearing failure is more subtle, you may need to listen to the knuckle
with a stethoscope or a piece of hose up to your ear, as you or a helper
spin the wheel. Also, grab the wheel at its perimeter and shake it, like
checking bearing play on an old boat trailer. There should be NO play. If
there is, it could explain the clicking noises you are experiencing now as
well. By the way, sometimes you have to remove the brake pads to do
careful 'listening' to a hub bearing as the pads rubbing away on the disks
can be distracting. No big deal, just a few more bolts to round off... I
mean... remove.

Tom LH
1995 90q