So I was driving around this past weekend and noticed a slight vibration between 35 and 50 mph. When I got the chance I got under my truck and saw one of my u-joints was coming apart, wasn't actually loose that I could tell but coming apart where one of the caps seals on the inner cup. Have just shy of 300,000 on the beast and probably never been changed so I figured I'd do them all on the rear driveshaft. Didn't really have any special tools so I set each of the yokes on two pieces of wood and beat it down with a hammer. Now I've done it this way I don't even know how many times with semi-truck u-joints with no problem. Didn't take too much with a 48oz hammer and I put some pretty pretty good flat spots on my drive shaft and the thing shakes worse than ever now. Found a place that can replace driveshaft tubes but its probably going to cost in the region of $200-$300. Next time, might just cut them out with a blow torch and deal with the burning grease. 3/4 ton driveshafts aren't quite as stout as class 9 driveshafts.