1988 80 Quatt. w/ MT and AC---Differential Lock Up

[Dr. Cory Brayton]

I've had a similar problem but differential would unlock @>15mph

I also suspected I had vacuum problems dt HC>200 on emissions test +
sporadic engine light flashes --> I had significant vacuum leaks from old
hoses + intake boot

since repair I think brakes are better, I've not had the differential lock
problem & no engine light flashes

I'll be interested to know how your vacuum system is doing & if it is
involved in your differential problem

I may have a switch problem too & it may just be coincidence that I've not
had the problem since the repair

Cory Brayton, D.V.M.
88 80Q
Houston, TX

> To:
> Subject: 1988 80 Quatt. w/ MT and AC---Differential Lock Up
>
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> Do you happen to know what might be the problem with my car (88 Audi 80
> Quatt w/MT and air)? I went to engage the rear differential. The ABS OFF
> light (on dash.) came on and the rear wheels locked in--as expected. The
> problem is that now the ABS OFF light will not shut off and the diagram
> indicator (near the emergency brake) will not turn off. The lit
> arrow on the
> actual DIFF button will turn on and off when I go faster than 15
> mph or when
> the DIFF button is depressed. The car itself seems like it has
> remained with
> rear differential locked. For instance, the car is difficult to
> turn at slow
> speeds. In addition,  there are two knocks from the front end
> after the car
> comes out of the turn. I have driven the car faster than the 15-20 mph and
> the rear will not disengage. Anything you might know and could
> pass on would
> be of great help. By the way, repeatedly pushing either the ABS button in
> center console or the DIFF button near emergency brake seems to do nothing
> other than light and unlight the arrow on the DIFF button.
> Thanks
> Blu