Ford F-150 U Joint Replacement

My husband is going to replace our u-joints in the rear of the truck this weekend, at least that's what we think is wrong. We have a vibration while decelerating between 60 - 52 mph. I have talked to many mechanics and they all are pointing me to the u-joints. Does anyone have any advice on how to do them the easiest way ourselves without taking it to a garage. He is going to do it Friday morning when he gets home work work because we are going out of town on Saturday. Please e-mail me with any advice or instructions on how to replace them that would be helpful. Thanks ahead of time!