Yesterday while driving down the highway I heard a loud pop. It sounded like I threw a rock from one of my tires and it hit the inner fender. I didn't think anything of it until this morning when I walked into my garage and found a puddle of gear oil under the rear of my truck. There was a small hole in the diff. cover. When I opened it up I found one of the pinion teeth had broke off and then got pitched throgh the cover by the carrier. Has anyone else ever had this happen. The rear end has been maintained regularly and I dont hammer on my truck.