GMC Sierra C/K 1500 Forum : “i have a 92 GMC Z71 and my 4wd wont lock in”

my buddy has a 96 gmc sierra with similar problems what all he does is when he needs it he has to engage and disengage it just keep fiddling with it then it should hook up. try driving with it engage till it hooks up

my truck did the same thing you might need to replace the front differential solenoid actuator. thats what was wrong with mine