I think it is safer and faster to jack up the truck fully from the rear diff, then place the jackstands under the frame, just ahead of the front spring hangers. This way, you can just raise and lower the rear end out of and into position as needed without having to move the whole truck up and down. The first time I did it I thought I could do it without removing the wheels....NOT. Once the wheels are off, it should take less than 15 minutes to do the job.