Grinding noise under accel....pinion bearings???

So after replacing my diff bearings, whihc looked like hell. I still have my grinding noise. Though the loose bearing noise is gone, it still grinds under acceleration, the noise goes away when I let off the throttle and then rears its ugly head when I come to a stop or under 30 mphs, it sounds like the coast side of the gears are meshing.......badly.

So, has anybody else had this type noise? When I setup the backlash I could only get it to about .010", what is the spec? I though it was some where around .008", but I can't remember. Is my backlash too open? The pinion has no noticeable play in it, thats what has me thrown. The u-joint seems tight, and the noise doesn't sounds like worn joint noise, I've had from the past, of the vibes, its just a grind type gear meshing noise.

Any ideas????