ok, according to another post i started, a diagnosis is that i have a rooted pinion bearing. is the replacement of this bearing a tough job? i have never rebuilt a diff or gearbox, and are contemplating doing this repair. do i need to set "pre loads" and shims and the like, which i have no idea about and details like that scare me. simply asking, is it an unbolt, replace, bolt back together, or is it a touchy, balance this, preload that type job that i will end up stuffing up. time may be on my side, as i may be able to borrow another cruiser for the time out the FJ may need, so being a DD won't be a limitation. also what type of special tools do i need??