I did the same on my 91. It wasn't too difficult except when I had to remove the axle from the truck. Was a tight squeeze to drop it down and out. Might have been because of my lift kit. The FSM stickied in the forum has all the info you need to get it done. I wouldn't wait too long because any driving in the rain will wash out the grease and then the CV joint will eventually fail.

91 SR5 Xtra Cab, 298000km, 4" lift, 56" rear springs, 33-12.5R15 BFG Mud-Terran T/A KM2.....and an '85 axle still waiting to go in.