Just did mine yesterday (93YJ 4.0) Just make sure you have the correct sockets and extensions (of course) the new pan gasket, rear main seal, and some good RTV (I like Permatex myself). I would also recomend getting a small brass drift punch for popping the new seal out. Once you take the pan off and the rear main cap off you can eaisly tell how that little seal comes out, and just remember that inside the seal is a metal piece that gives it it's shape, when your taking it out and installing the new one just let the seal follow the shape of the crank, it's round and so is the seal so it will slide "around" it. I know that is a bit confusing but once you see it for yourself you will understand it.
Good Luck, and an extra pair of hands is also nice to have when putting the pan back on!