Re: Differential Locking Problem '88 5KCSTQ

[hugo@knoware.nl (Hugo van der Vlist)]

On 16-SEP-95 Keith Choate wrote:

>Hello All,
>   I've been having a problem recently with my front and rear differentials
>locking spontaneously (with the selector switch off) at high speed.  This
>seems to happen more often in fourth and fifth gear when turbo boost
>exceeds 1.1 bar (60+ mph). etc.

Keith, I had the same problem on my 84 TQC. The locks work on vacuum
provided by the inlet manifold. But when the turbo starts to boost there
will be no vacuum left. Of course the Audi engineers knew that as well, and
placed two valves in the vacuum lines. One can be seen under the hood near
the steering fluid reservoir (in my case a blue/black thing, one inch
long), the other is under the dash. One of those can be faulty. Try
replacing the easiest one first. If that doesn't help you can put an extra
valve in the line that goes inside so you don't need to take your dash out.
By the way, cars equipped with airco have two vacuum valves under the hood
AND a valve under the dash.
Hope this helps.



Hugo van der Vlist
the Netherlands

'84 TQC
'85 Coupe Q