Changing ring and pinion is not too bad but it is much easier if the rear axle is on the bench rather than laying under the car.

You will need four specific tools, a regular lb-ft torque wrench, a lb-in torque wrench a bearing spreader, and a dial indicator. You should be able to find instructions on the web (rather than drag thru them here).

When you buy a ring and pinion, also buy a new crush sleeve. A crush sleeve sets the pinion depth.....the sleeve is a tubular spacer designed to collapse when an axial load is applied. Since your old crush sleeve is already "crushed", you cannot expand it to start over. The crush sleeve takes the place of shims found on Dana pumpkins. Crush sleeves were invented so, at the factory, they didnt have to disassemble the pinion to add/subtract shims..
....they could turn the pinion nut until the right "crush" was achieved. It saved time.

If in doubt, use new bearings on the carrier and pinion. You will have to press them on hence the bearing spreader to pull the old ones off. Your local auto machine shop can probably do the pull/press for you. Do not pound the bearings on with a hammer!!

I think that Drivetrain Direct or Randy's Ring and Pinion have setup instruction sheets that put it in simple words. On the bench, you should be able to change the ring and pinion in about 3 hours.

mike in tucson