Usually when the rear diff doesnt work it is because the shaft is frozen in
the sleeve. sometimes it is the servo. the servo is the easy fix. it is only
about 200$ at your dealer. and about 2 hours to change if you have never done it
before. If the shaft is frozen, it is a lengthy fix. tranny must come out and
bell housing off. then dependin on how bad the corosion is you might need a
new sleeve and/or shaft about 200$ aT YOUR DEALER. the labor will kill you on
that one.

good luck.

Chris
VT