Is a rear end gear change something you can do it your driveway? Are there any parts needed besides the new gears and gasket? I have done a lot of car work over the years, but never a rear diff.
you need various carrier shims, pinion shims, a crush sleeve, a pinion seal, and gear paint/paste... or just get an installation kit which also comes with pinion and carrier bearings.
some additional tools: shop press inchpound torque wrench pinion depth tool or depth micrometer (using a depth micrometer requires calculating bearing center).
i had the rear end out and sitting on stands. my kit also came with a video. between the service manual, video, and online forums, i got it done.
If you do it yourself use the old crush washer until you get the proper pinion depth .. crush washers can only be used once.. had a good article on it a couple of years back in HPP.. saved the article myself.. planning to replace the gears in my car some day.
i set the pinion depth and gear pattern without any crush sleeve installed. that's how the video said to do it. once i got everything set correctly, I installed the crush sleeve and tightened the rear nut, measuring preload w/ the bitty torque wrench. then rechecked the pattern... it was same.