If you have never done , nor seen some one set up ring and pinion gears.. its best to take them to a axle shop and let them do it, a small mistake here will explode your gears, and passably your locker on the trail or road.
If you want to jump into them yourself.....
First off take a die grinder to your old bearings and grind there I.D.'s till your able to just slip them onto your new carrier, and Pinion gear.
This will aid in setting up the proper pinion depth and pattern by allowing you to change out shims and not having to press your new bearing on and off a dozen or so times.
As to getting the new bearings on, place them on a cookie sheet and bake them at 250 degrees for 45 minutes and install them hot, a slight tapping with a dead blow will seat them for you. (note its a good time to send the wife out will a few dollars and told to shop all day)
Also bake your ring gear...it helps in getting it seated on the carrier. As to the bearing races for the new pinion gear bearings...freeze them the night before...I prefer using dry ice just because its colder than the freezer, liquid nitrogen is the best method but not everyone has access to it. And Dry ice works just fine with a little persuasion with your trusty dead blow.
If your set up has a crush sleeve to set the pinion pre-load, buy several and keep the receipt, you always mess one or two up in the beginning.
Good luck...pm if you need more info or help.
