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diff locking stays locked !


> But now the front diff stays locked (the green light on the dashboard
> keep burning and and you feel it also) I don't know what to do to
> disengage it as the switch doesn't operate anymore. but this not the
> switch because the rear engage and disengage like new.
> Does anyone of you have any idea of the problem?
> Is it dangerous to drive with the front diff locked?

Bernard,    Yes it is VERY detrimental to your differetial, and
generally your whole front end, to drive with the diff locked, (actually
it only hurts it when you turn corners, but when do you go anywhere and
not come back?) I had this happen to me with my 93 90q, however all i
did was gently "wiggle" the diff, by turning slightly left and right and
driving slowly ( 10 kmh) and trying the switch as i was moving. I have
used my locking system since then, in a straight line, and haven't had
any trouble.


No. 1 - You can't lock the front differential, the system in your
quattro GT coupe
allows you to lock the center and rear diffs. You probably locking the
diffs by twisting
the diff lock switch in the center console. Correct?

No. 2 - With the factory Audi quattro system in a 1993 Audi 90, you
can't lock the
center diff. The center diff is a Torsen. You can lock the rear diff by
pressing a

Now, from the sounds of it the center diff is locked and won't release.
Turning the
switch pulls a vacuum on a solenoid mounted to the right side of the
tranny. Look
by the output flange on the tranny and you will see the solendoid, it
has 2 ports
on it and the vacuum lines go through the firewall to the switch. An
actuating rod
is pulled by the solenoid to lock the diff.  To unlock I would pull each
of the vacuum lines from the solenoid to release. Then if it is still
locked, the actuating 
shaft might be binding, crawl under the car and try to move the rod and
see if it is stuck.

As for damage, it probably won't happen driving around with the center
diff locked for
a short time. Driving 5k miles with it locked on dry pavement might
induce some wear.
All that is happening is the drive torque is being distributed 50/50 to
the front and rear 
axles. The front and rear axles are still able to compensate for side to
side changes in wheel
speed, since they are not locked.
Dave Lawson
86 gt
83 ur-q