The auto-locking hubs on my 94 Bronco XLT have seemed to have stopped functioning correctly. When the 4WD button in the cab is pressed, I can here some clicking and the voltage gauge fluctuates, which I assume indicated that the servo that engages the front hubs is moving or at least activated, however
front drivetrain does not engage. I recently had new front brake pads & rotors installed, and the front hubs were re-packed. Prior to that the auto-hubs functioned flawlessly (as unbelievable as it may seem). Could the shop that performed the brake job have possibly packed the hubs incorrectly? Or is it more likely that the auto-hubs finally lived up to their reputation and simply died on me? The truck has 120,000 miles on it and has not seen
much in the way of hardcore wheeling, just some light mudding every now and then. Also I put in 4WD once a month for about a 1/4 mile on straight roads to keep everything in the front lubed up/exercised. Any suggestions? I'm hoping it's a simple and cheap fix, but if the hubs are shot I'm guessing it would better to install manual hubs.

 

Your auto hubs have finally lived up to their reputations. This isn't the shops fault. Best thing to do is go out and buy a set of Warn manual hubs. They're the sturdiest out there.