I sold my 1999 Cherokee XJ a few years ago, but this page gets a lot of hits, so I'm leaving it alone so others can benefit from it.
This information is here because I wasted too much time on a web search trying to find it: The Jeep (Aisin, actually) AX-15 transmission used in XJs has a fluid capacity of 3.3 quarts (3.15 L), although realistically you won't fit more than almost 3 quarts in unless you disassemble the thing to fully drain it. Chrysler thoughtfully declined to include this in my 1999 Cherokee owner's manual. The fluid type is GL-3/GL-4 75W90 gear oil, such as Redline's MT-90 stuff.
The Randy's Ring & Pinion part number for the outer axle shaft of a 97+ XJ Dana 30 is DAN43205. The price (July 2004) was about $35.
Specs of the outer axle shaft are: 6.11" long, 27 spline, 297-style u-joints.
The front axles take Spicer 5-297X (old part number) or 5-760X (new part number) u-joints.
The Chrysler 8.25" rear end uses 9-inch rear drum brakes. I guess that means the D35 uses 10-inch ones.
Brake tools (the little spoon things) are worth the money!
When you buy new drum-brake shoes, buy the hardware kit too. It's got all the springs and whatnot in it, so you can just throw out the old ones, or keep them for spares.