Quattro Differentials?

[tturse@ps-b.com (Thomas Turse)]

I know this has probably been mulled over hundreds of times, but can anyone
give a brief summary of when you can and/or should drive w/ the center and
rear diffs locked (85 4ksq), and the handling effects of each.  Also, is a
the car actually 4wd all the time?  I noticed that the 85 manual differs
from the 86 and 87's in the do's and don'ts and when to use the locked
differentials.  I'm particularly interested in their use in driving on snow
and ice.  I have been unable to lock the center because of a bad vacuum
switch, but used the rear lock to get out of the snow when the car was stuck
a few times.   Just curious about the benefits of having a locking center
differential.  As always, thanks for your thoughts.
BTW, my two labs like my car or any car they can get into for that matter,
but my back seat is covered in black and tan hair and the windows are always
crusted w/ drool.  I usually try to vac it once a month so it doesn't get
too bad- in my GLI, I went about 6 mos. before cleaning up the hair and it
took hours and a few rolls of duck tape to get it out!

Sincerely,

Thomas C. Turse
Boulder, CO
85 4ksq
tturse@ps-b.com