Well there's a little more to it than that but not alot. When you remove the old one you need to clean everything real good. Mark the caps so you put each side back on where it came from. Then take out the ring gear bolts and take the ring gear off the old S/G unit and put it on the new one. BTW: The ring gear bolts are left hand thread and you need to apply a little bit of loctite to the threads. You also need to clean up the threads good before you re-install them so you get a proper torque reading then torque them to 55 ft. lbs. Then install it and just snug down the cap bolts and preload the bearings then set the back lash using a dial indicator. The backlash clearance is .005-.007". Then torque them to 80 ft. lbs. You also need to apply a little loctite to the cap bolts.
Also keep in mind that very rarely does a new S/G unit come with bearings installed so you'll need to have new bearings pressed on.
