gear and pinion set up 8 3/4 489 case

The biggest tip I can offer is to hone the old large pinion bearing until it is a slip fit on the new pinion gear. That way you won't have to keep pressing the bearing on and off getting the shims right and risk destroying the new bearing. When you get the correct shim that gets the gear depth right, just press on the new bearing. As long as the old bearing is still in good shape, you won't see any difference from the old to the new bearing. As far as backlash, I always set it up at around .005-.008". After a while, you won't need a dial indicator anymore.