hey guys,
i have a 2003 with 9.75 rear end about 5 months ago i took it to a local shop and had the pinion seal replaced. the guy never filled the rear after or torqued the pinion nut a bout a month later the rear went so i replaced the bearings to get myself home.i have since replaced all the inners of the rear minus the pinion race and the u joints were also replaced trying to get rid of the vibration any ideas would be greatly appreciated

Thanks alot,
codey

 

Your driveshaft might not be balanced or your axle shafts are messed up.

 

When you replaced the bearings in the diff, did you inspect the axles carefully because the lube in the diff lubes the axle/bearing wear surface? I don't know, the whole thing should be carefully inspected and rebuilt. Not torquing the pinion would cause the ring gear and pinion gear to be misalgned and ruined. I would think the gears need replacement. It's not clear in your statement if than was done.