A friend brought me over a (New to Him) AMC 20 with maybe 100 miles (PO went a different route), the PO geared it up with 4.10 and a locker.. When I checked it out the pinion was loose (slop), I told him I would rebuild it just incase because you I dont trust some people.. I tore into the axle and there was bearly any wear but the bearings didnt feel new and yet didnt feel old.. I noticed the crush sleeve wasnt crushed eitherand it didnt feel like the outer bearing was properly seated.. Anyways I go ahead and rebuild it.. The only problem Im having is that now after setting it up with a set up bearing, I put the new bearing on and its tight, I mean stripping 3 pinion nuts tight 3 different times before the bearing is seated (1st one original and already messed up) The pinion threads are fine and its the right nut.. Ive never delt with a bearing being so tough, Im almost wondering if the pinion might be bent or the bearing is, Im thinking about putting the pinion on a lathe and checking and or take some sandpaper to it to take about a .001 or more off.. Has any one ever had this issue with the axle?

Am I to understand you are using the pinion nut to draw the pinion through the bearing, thus pressing it on? If so, why would you do this? They make a thing called a "shop press" that will handle this sort of thing with ease. If you are having some other problem that I am not understanding, ignore the previous statement.
Travis..

I cant get the whole axle in the Press.. Typically thats what you do when your trying to put the pinion together, Its the forward bearing..

must be wrong bearing, I put one together yesterday and I pushed the bearing on with very little effort, just measure the inside of the bearing and the outside of the pinion and you should have your answer..