I did mine last year. I have a set of Factory Service Manuals. I did find a TJ FSM for the AX-15 online somewhere. Some googleing should get it for you, that will take you through it step by step.
*edit* try this
http://oljeep.com/tcase/jeeptransmission_AX15.pdf
There is a "5th gear upgrade" which I could not find any reason to buy and install, so I bought and installed it anyway...
Caution when you remove the shift rails be super careful about the little shift rollers. I lost one and could not find it from any one. I ended up making one from a bigger one by putting it in my drill and using my grinder to grind it to the exact right size. I keep expeting that little bugger to turn up on my shop floor but I still haven't come across it.
As for fluid it seems like nobody can agree on what is best, I am running the Redline MT90 which seems to be the least controversial choice. Although there are strong arguments for running motor oil. After being rebuilt mine still "clunks" into 2nd gear when cold. Before rebuild it "clunked" into just about ever gear.
If you actually need gears you can track down some toyota parts and get a lower 1st gear. It probably isn't worth the expense unless you need gears or can find the right junk yard toyota box.
Nathan