my truck has a grinding noise in first and in drive under load.Thought it wa a pinion bearing but it is not constant thru all gear changes

 

The truck had a bent axle and I replaced the axle,axle bearing and seal,pinion seal all 3 u-joints and center support bearing.I also replaced brake pads on all four corners and parking brake shoes on both sides. But I still have a grinding noise similar to bearing noise in 1st gear and in drive only under acceleration,and in reverse.