Basically, what FastEddy means is: don't drain something you can't refill. The plug he's referring to is on the side of the transmission, and there's another one on the side of the transfer case. They have square heads as I recall. Simply unscrew them first. It will be fairly obvious once you crawl underneath. This is where you will have to add the new fluid, and it has to be pumped up there because there's no way to pour it in as the body and frame of the truck are in the way. I bought a little plastic pump that screws onto the bottle of 85W-90 gear lube and I just put it in the fill hole and pump until it runs out of the same hole, meaning it is full. It's messy. The stuff stinks. Fair warning.

John B.