Nytemare

your front 4wd actuator in the diff is gone is gone, or the fuse/relay that gives it juice. unplug it and test for voltage at the plug..if you have voltage than the actuator is gone...no voltage its the fuse...or relay DORMAN Part # 600101...4wd actuator from Rockauto. 83 bones

Are you more scared of paying out what GM wants to fix it...or rear ending someone and having to pay out the cash for an insurance claim? Bet GM isn't charging you anywhere near what your insurance will charge you, for both your deductible and your increased rates for the next few years.