5kq Center Differential "Sticky" Disengagement

[Dale McCormack <profit@mcs.net>]

Fellow Quatrophiles:
For the past several winters I have had difficuty in getting the center
differential to "unlock" after turning the dial control.  It is not a
malfunction of the advisory lights as there is an audible groaning
immediately upon steering the front tires on dry pavement.

My "cure" has been to patiently drive slowly around a large parking lot
occasionally steering from side to side until the lights go out and the
differential unlocks.

When I spoke to my dealer's Service Manager (Laurel Audi, Westmont IL)
he seemed unconcerned with a "they all do that" response.  I personally
doubt it. 

During my ownership both diff lubricants and trans have been changed
twice (every 50K) with synthetic gear lube.  (Based on recent on-line
conversations this later information may be helpful.)

Since one cannot always count on the luxury of a large parking lot after
locking-up center or rear differentials before turning them off and
making a turn, I want to fix this ASAP.
TIA