[s-cars] Transmission swap & alignment

[Fred Munro]

Hi Steve;

Your description of the rattling noise that goes away when you depress the
clutch pedal leads me to suspect that you have issues with the pressure
plate mechanism or a release bearing that is flopping around. Something is
loose and rattling with the clutch pedal out, but when you depress the pedal
and put pressure on the mechanism, everything tightens up and the rattling
stops. Vibration in the clutch pedal is usually caused by a bad release
bearing or broken pressure plate springs or fingers. Vibration in the
driveline on take-up can be a warped flywheel, damaged clutch disc or
damaged pressure plate. A bad release bearing usually won't cause the
driveline to vibrate but it will shake the pedal. Did you install a new
guide sleeve for the release bearing? Metal or plastic?
The only clutch problem I've ever had was broken pressure plate fingers and
when that happened the clutch wouldn't disengage and I had to rev-match my
shifts all the way home.
Unfortunately you may have to pull the tranny to see what is going on. You
may be able to pull the starter and get a look with one of those fibreoptic
inspection cameras.

Good luck!

Fred Munro
'97 S6

-----Original Message-----
From: s-car-list-bounces at audifans.com
[mailto:s-car-list-bounces at audifans.com] On Behalf Of Steve Voit
Sent: Saturday, June 30, 2012 3:56 PM
To: s-car-list at audifans.com
Subject: [s-cars] Transmission swap & alignment

Lookin for technical s-head help:

Maybe 40k miles ago my wrench swapped out the original trans for a 6-speed
from an '01 S4 along with a brand new dual mass flywheel and clutch.  (I
could look back to see the trans designator, but it is not really material
for my question)  The ratios are fantastic and this has been one of the best
mods.  I love it and the Apikol short shift kit.

 

The install performed smooth as silk until, at one point - I'll say abruptly
10k miles later - I got significant pulsation/vibration upon take up.  What
is puzzling is that it started suddenly, not some funky condition that
appeared over time.  I've solved the issue by changing my driving style to
use slightly higher revs and a generally quicker clutch to get a smooth
start.  If I'm in a delicate parking maneuver, however, there's a lot of
pulsation felt through the pedal and the seats.

 

I've also noticed when waiting next to a wall at a drive thru window that
the car makes a sort of rattle-y noise when the clutch is out in neutral,
which kind of goes away when I put my foot in (also in neutral).  This seems
to be the opposite of my experience with manual cars, generally, which get
quiet with the clutch out.

 

What might cause this?  I know there's no way the trans is perfectly aligned
axially with the engine as well as was the stock one; only 1 locating pin
fits (not 2) and so I and others just Happersized the trans into the best
fit via seat-of-the-pants.

.         Did a misalignment cause something to wear/break?

.         Did I coincidentally have a crank damper move?

.         What do you think?

 

Steve Voit

Seattle

95.5 S6 130kmi

 

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