the pinion bearing out of my truck stock and the pinion bearing I got in my install kit are different. whats up with that, is it something I have to do different to set them up? the stock oem bearing has smaller bearing and race, vs the new replace meant is bigger bearing and race.

 

Depends on which pinion bearing you are talking about. There are 2.

There is an inner bearing/race (has to be pressed on to the pinion gear) and the outer bearing/race (behind pinion nut).

 

Yes they are different, you must replace the race also