I am in the middle of this right now. It started out as a pinion bearing noise/ leaking seal. With new pinion bearings and seal in hand I dove in. when I got things apart I found the differential carrier cross pin was severely worn down and carrier case (open) was toast. so I ordered a rebuilt trac lok ( the re builder left out the troublesome clips that always break, I wasn't comfortable with that so I ordered new clips and the tool to dissemble/reassemble said trac lok) ordered 4.56's, special notched crosspin and new ring gear bolts as recommended by the FSM. I also had to purchase more bearings for the carrier and axles. ( I also found scoring on my factory axles where they ride the outer bearing, found nice used ones at the pick and pull.) I have purchased for this job also a 0-60 inch pound beam style torque wrench for setting up pinion preload, a tool to adjust the carrier adjuster deals, a tool to hold the yoke so you can tighten the pinion nut, marking compound, shim kit, loc-tite, oils, LSD additive, I still need a dial indicator w/ magnetic base and I think I will be all set.
Now my truck isn't my daily driver, I literally have it just to kind of tinker with. I have really enjoyed researching, learning, and even buying this stuff(completeoffroad.com!!)
That said doing this myself is proving to be a really long and expensive way to rebuild the rearend w/ gears.
MORALE OF THE STORY: unless you want to learn about your truck, collect some tools you may only use once, have it take a bit longer, and always question how accurate your first attempt at setting up a rear end was, leave it to the dealer or experienced shop.
Buying your gears, master rebuild kit, LSD/locker of your choice (new), and getting them installed professionally in my opinion is the best route cost wise and piece of mind wise.