I have found that driving in deep snow introduces a condition in which the
diff lock may not engage. I have failed to find out why, however, but
noticed that after the vehicle is above freezing for awhile, the diff lock
again works fine. I speculate that packed snow or ice forms under there,
and impedes mechanical operation. Either that, or below freezing water
freezes solid in the vacume lines and as a result the information does not
get to the trans telling it to engage the lock.

At 02:20 PM 6/18/98 -0600, you wrote:
>last night i was up driving around Alta, UT in about 1.5 ft of fresh
>snow...yes it is mid june.  and i got a bit stuck.  i pulled my diff
>lock knob, while stationary and in neutral.  then i put it in first and
>tried to pull out.  drivers left and rear passenger (right only, i
>think) wheels spun---no locked rear diff and no green indicator light.
>it has worked in the past, but this is the first time in a while that
>i've needed it.
>
>recently there was a thread about diff lock problems, fixing and or
>diagnosing.  i searched the archives from 1 june to 16 june on diff or
>differential, but didn't come up with exactly what i was looking for...
>
>what is the proper way to diagnose the problem with my diff lock,
>starting with most likely first, since it has worked nicely in the past.
>
>thanks,
>fred
>
_____________________________________________________
Derek Drew                           New York, NY & Washington DC
ConsumerSearch
drew@interport.net
212-580-6486 (W)
212-580-4459; 202-966-0938 (H)