4000q diff lock trouble...

[mallick@orion.crd.ge.com (John Mallick)]

Hi Folks!

Well, I'm trying to get the ol' 84 4000q in shape for winter, and it
appears that the differential locking is having problems.  The rear
diff doesn't want to lock at all, and the front is sort of
intermittent.  Suspecting a vacuum leak, I started my usual routine of
sucking on vacuum hoses and found that the differential lock main hose
didn't offer the sort of resistance I expected.  The locking servos
seem to be OK, and it is looking like the lock control valve itself
may have a bit of a leak. Is this normal?  The accumulator is OK, too.  

I plan to do a thorough vacuum hose replacement at the rear diff this
weekend, but I wonder if anyone has ever encountered a leaking control
valve. 

John Mallick
'91 200q
'84 4000q