I've rebuilt a couple of them. Pretty easy job. Just go slowly and pay attention, and document the order of disassembly and position of the components.
You need a minimum of 3 u-joints, preferably 4 since you are likely break or drop a needle bearing, and preferably the Spicer 5-153X joints. The centering ball yoke is Spicer part 211355X and is complete with ball and spring. Total cost for 4 u-joints and the yoke is about $100 from northern drivetrain. The zerk fittings that come with the u-joints can be hard to reach when the driveshaft is installed so I like to use the low-profile zerks and a needle fitting on the grease gun. McMaster-Carr sells the low-profile type, item number
10595K14 is the 1/4" x 28 pitch, about $2.50 for a pack of 5.
The u-joint at the yoke has to be separated from the CV joint before the u-joint can be removed from the driveshaft. Reassemble in the same order.
The ball and spring assembly is kind of irritating. The end with the cup has a nub shaft sticking out (male) with a hole in the center for the spring. Meanwhile the centering ball has an opening in the center (female) that is lined with needle bearings. The spring goes into the nub, and the nub goes into the hole in the ball, and the nub rides on the needle bearings. You need to lard this up with grease pretty well--there is also a small flush-mount zerk fittting that can be used to regrease later but it is very hard to reach with the shaft installed in the jeep.
Another tricky part is that you have to do all of that while also installing the u-joints. If you get the angles wrong teh parts will only go in about half way then jam up on each other. Look at how the parts must be oriented when they are squeezed together and it will be obvious.
The grease fittings on the yoke need to be outboard of the centering yoke when everything is reassembled.
