I replaced mine too if i can be of help, darkrunner gave me the directions though.

Here is what DarkRunner told me:

"Make sure you put the gasket on correctly. It will seem as though it doesnt fit if you put it on backwards so just flip it over and it'll line up. Also soak it in water while you're removing everything, this makes it more flexible so theres less of a chance of it ripping while you're putting your new diff on and also use some silicone.

Make sure to take your wheels off before you remove the axles cause its a pain in the ass trying to get your axle splines lined up with all that weight. Be careful of your axle seals (just make sure you dont rip them). If you have abs you dont need to remove the sensor. Make sure to put a clamp on your brake line.
If you have the locking diff you'll have to remove your gas tank skid plate and your anti-roll bar (not the whole thing, just where its connected to the axle, then push it up and hang it) to get your diff in and out. Also, put your axle on jack stands then use another jack to lift the frame and body off the axle. Its not necessary but it gives you a lot more room to work and makes everything much easier.
That should be it. If you run into any problems or have any more questions, feel free to ask."

Darkrunner said it would take 4-6 hours (He did it on his driveway with handtools), it took me about 2 hours and 45 minutes but i also used a lift and power tools in a shop.

__________________
97 4runner 3.4l 4WD 5 speed Cupholder Mod/99+ Center Console Mod 3rd Member Install