Pretty easy really, I jack up the rear and put it on jack stands. If you get the rear up high enough, the oil doesn´t leak out the rear of the tranny (much) when you pull the shaft. Take the half round clamps, off of the bearing caps on the drivehsaft U-joints (mark the U-joint and yoke so it goes back together like it came apart). Hold the caps on with your fingers and push the driveshaft forward, the front yoke will slide a bit into the tranny so the U-joints clear the rear yoke (might have to pry a bit with a large screwdriver). Have some tape or something handy to take make a loop over the caps, so they don`t fall off, or you´ll be hunting for roller bearings. Pull the driveshaft to the rear and the whole works, will slide out the back of the tranny. Best to have a bucket under the back of the tranny and a rag handy just in case.
Pry out the old seal, coat the new seal outer rim (the part that slides into the bearing well), with a light coat of silicon sealer (after wiping the oil off with a little solvent, the cleaner the better the seal). Keep the seal as straight as possible when putting it back in. Various methods for reinstalling it, I use a small hammer and a small piece of wood and tap around the edges at first on opposite sides, then when it starts in aways, I tap it in a circle, a little at a time. So it seats, alowly and evenly, if you hit it too hard, it can bend the metal rim, on the seal (there is a special tool for this, that I´ve never seen). I´ve used a big socket, that matched the diameter of the seal to tap it in. I always grease the seal lip, with a finger full of grease, maybe not necessary, but why not, it would be a bumber, to have your new seal get hot, from lack of lube.
Also mentions in the book to try and get the front yoke, onto the same splines, that it came of, I never bothered, it never seemed to hurt anything.
If your new seal doesn´t last more than a few months, your probably gonna have to buy the tail cone. The bushing is in the tail cone and the book says the bushing is not replacable. Though if I ever did have a cone bushing go bad, I´d probably try and do it myself, bushings are cheep. I´ve done it on other transfers and trannys, not easy but doable.
Not a bad time to take a close look at the U-joints, if you can wiggle the caps left and right, it´s probably time for new U-joints. Bad U-joints can also cause the seal to wear quickly.
With the seal off it´s pretty easy to measure the play between the yoke and the bushing. If you push the yoke to one side, on a good bushing, I´ve measured about 0.003, between the bushing and the yoke, with a feeler gauge.
The bolts holding the half round clamps on the U-joint caps, have been known to snap off, loosen carefully and don´t over tighten when reinstalling. I seem to remember having a bit of trouble finding a socket to fit. I usually use a little dab of thread locker (mild) just in case, during reassembly.
