Did this a month ago when I needed to replace an axle shaft with a pitted bearing surface. I transferred the tone ring from the old axle to the new axle. The tone ring is pressed onto the axle shaft. Before doing this I'd make sure that the tone ring is actually damaged. It's not a 30 minute job, more like a couple of hours. You'll need an axle bearing puller if you're planning to replace the seal and bearing (which I would do if you're going to be pulling the axle).
After securely raising the rear of the jeep, you need to:
1. drain the rear diff oil (remove most of the fluid with a fluid remover through the fill hole if you don't like messy, or just let it fall out when you pull the cover in step 2)
2. pull the diff cover and clean off all the old gasket from the cover and the diff (you're going to need a new gasket or gasket maker to reinstall)
3. remove the pinion shaft retaining bolt and the pinion shaft and keep it in a clean place (careful when removing the retaining bolt because the pinion shaft is heavy and will slide out on it's own if the diff is in the right position, and you don't want it sliding out onto the floor and being damaged)
4. remove rear tire
5. remove rear brake caliper (hang out of the way with a bungee)
6. remove rear brake rotor
7. now you can push the axle in about 1/2 inch (be careful not to damage the abs sensor. the axle shaft can make contact with it when you push in)
8. remove axle c clip inside the diff (it should drop right out, you might spin it around til it does. if it doesn't then the axle isn't pushed in far enough)
9. pull the axle out of the housing (careful with the seal if you plan to reuse it) at this point you should check the surface where the bearing rides. if there is pitting, you should replace the axle. you might even find an axle with the tone ring already pressed (check a wrecking yard). my new axle did not have one.
10. if you're in this far, you may as well replace the bearing and seal (you can get a "repair" bearing that has a bearing sandwiched between two seals, they come as one unit. If you look down the axle housing you'll see a bunch of rust and junk, and the inner seal's job is to keep that stuff out of the new bearing. be sure to use proper grease on the bearing, and a thin coat on the seals will help prevent seal damage)
11. also check the condition of the e brake shoes with the axle off. sometimes the friction surface de-laminates from the shoes and can be left banging around inside the rotor. replace them if needed. this is the best time to do an e-brake service because the axle is out of the way and it will be a million times easier. I'll leave it up to you if you only change one side and not the other, although I don't think it's a good idea to only do one.
12. now, get a propane torch and heat the old tone ring. (Note the position of the ring on the shaft, because you'll want to match the new ring's position to this pretty exactly in terms of how far down it is pressed on.) It should eventually change color, probably will look a little blue greenish. Takes about 20 minutes with a propane torch. heat it evenly all around, and direct the flame at the ring and not the shaft. When it's good and hot, take a pry bar or big screw driver and lever the ring off the shaft all around the circumference until it's free of the shaft and can be pulled off (with pliers cause it's hot!)
13. heat the new tone ring (propane torch or throw it in the oven at 450 for 10-20 minutes)
14. drop the tone ring onto the shaft, and gently tap around the circumference until the position matches that of the old one.
15. spray it down with some wd40 to cool it off. it will shrink fit onto the shaft as it cools
16. reinstall everything in reverse (don't forget the diff oil. two quarts of 75W90 I believe)
hope this helps, and I hope I didn't forget a step
Tim
