mark the driveshaft at the rear end with some chalk or something to make sure you re install it the way it came out. remove the two u joint straps. make sure truck is chocked the wheels so it doesnt roll (yes ive had a truck roll with me under it and drag me out of a driveway lol). Remove the 4 bolts holding the rear ujoint to the yoke. remove the straps, pull drive shaft wrap the slip yoke with a rag, have a pan handy for any fluid that might drain out if your on a hill. Pull the old seal out with whatever method you chose I use a small old flat head and work around the lip slowly. Put new seal in the correct way so the rubber is pointing out, use a small block of wood or large socket to put in evenly and slowly, lufe the rubber slightly re install drive shaft, torque the bolts to 20 ft lbs i belive and your done.