A buddy was driving my Bronco when all of a sudden the hub decides to shear apart, shooting the hearings, warn hub, etc to the side of the road. It looks like just the caliper is keeping the wheel on. What could cause this? I haven't been able to really investigate this, the wind chill is well below zero right not. I did install the warn hubs last year; they were working great; he was in 2wd (I assume/hope at least) on the highway when it happened.