To change the pinion bearings, you have to remove the rear cover, take out the axles and the carrier and ring gear assembly. Then, remove the big nut on the flange. You then need a puller to pull the flange off the pinion and take the pinion out. You will need a press to put the large bearing on the pinion, and something to seat the new races into the diff housing. You shouldn't have to worry about backlash and play in the gears since you are only replacing bearings, and thats if you get the new spacer crushed correctly. It is always good to check backlash anyway. Good luck and let us know how it goes!!!