Very easy.
1.Jack up truck, remove wheel.
2. Unbolt caliper from spindle (2 bolts in teh rear) and hand with wire/string from the upper control arm, with no brake hose.
3. Remove grease retainer cap from end of rotor, and then remove cotter pin, castle nut, spindle nut, washer, and outer wheel bearing.
4. pull on rotor to remove from spindle. NOW, the inner bearing/seal shoudl stay inside the rotor/hub assembly, but is some cases the inner wheel bearing gets stuck on the spindle. you may need to "persuade" it to come off. Take car not to chip,score, or generally screw up the spindle if you ahve to do this)
5. use a small pry bar to remove the inner wheen grese seal, and remove bearing from rotor/hub.
6.clean nout all the old grease and inspect the races. if they are smooth and uniform silver colored, no need to replace. if you see discoloration from heat, or can catch a fingernail on anything, replace them with the races that came with the bearings. There is usually a tool for rent at most auto parts stores that works great for this, no press required. If you are VERY careful, you can also uninstall with a screwdriver and a hammer. Either use the rental tool or the OLD RACE to pound the new race into place. A good trick is to put the new races in the freezer for an hour to slightly shrink the metal. this allows them to go in a bit easier. Also make usre ot use s mall bit of clean grease on the inside of the rotor to help install the new races.
7. using a bearing packer, inject grease into the new wheel bearing. if no bearing packer is available, use your hands and massage the grease into the bearing mannually.
8. liberally slather grease into the rotor where the rear bearing sits. place the packed inner bearing into the rotor, and install the new grease seal. take care NOT TO DAMAGE THE ABS TONE RING.
9. Place rotor on spindle making sure it is fully seated.
10. grease the outer bearing, pack extra grease inside again.
11. reinstall washer, nut, castle nut, cotter pin, and grease cap.
12. use non-chloinated brake kleen to spray off all oils and grease that may have made their way onto the rotors friction surfaces.
13. reinstall caliper, and then wheel.
enjoy the silence, no more growling on the road.
Another tip, remove and clean your ABS sensors while you are in there, its just two 8MM bolts to remove the cable, and pull the sensor out. Cheap insurance.