[urq] Center diff lock

[urq]

The symptoms are exactly what I'd expect with a failed check valve ... what
happens is that boost pressurizes the selected side of the actuator, which
is just like applying vacuum to the other section.  I would expect that
you'd have to be on boost for a while for the pressure to build up enough to
move the diff lock, and the actuator should return shortly after the
throttle closes.  

I suspect that if the check valve is bad that you will not have any vacuum
stored in the reservoir, so you might be able to do a test without taking
anything apart.  Go to the vehicle after it has been sitting a while (to
give the reservoir time to leak down).  Switch the selector to a different
position and listen for the hissing sound of air being drawn into the open
line.  

On my '83 the check valve for the diff lock is in the console, right behind
the lock switch.  

Steve Buchholz

-----Original Message-----

My suspicion is your check valves are failing or failed. Although usually
that comes with unlocking on boostm

----- Original Message -----

Lately my center diff lock is getting engaged on agressive accelerations,
mainly above 80 mph. The diff indicator light goes on briefly and you can
feel and hear this very loud thumping noise from the back end, very scary. 

This happened many times now and I'm afraid I ruined something. 

It's like there is too much vacuum and this actuates the switch or
something.

It's the 'later' style diff lock system with one rotary switch and two
lights.

Any thouhts?

Regards,
Maurits Jonkergouw