I have started to notice a clunking from my rear diff. I crawled under it yesterday and checked it out. The u-joints feel solid, no noticable slop. When accelerating and decelerating there is a clunk like a bad joint. I had my wife drive in back and forth and i knoticed a definate bind at the rear diff, and the shaft would turn abruptly at the same time as the clunk noise happened. the seal is leaking and gear oil has splattered around the underside of the tub. Do you think there is something seriously wrong with the guts, or just the seal and maybe u-joints should be replaced? Nathan.