You need one out of any 1984-1996 Jeep Cherokee XJ (not Grand Cherokee) or Comanche. They are the same shaft. If you have any trouble finding one let me know, I sell them on eBay, modified, repainted (you choose color) and bolt on ready, for $100.
I don't have any at the moment, I need to go pull a few more and get them ready, they go faster than I can find them. So let me know if you need one.
Also I plan to make a proper how to video to put on YouTube. (Some day)
The ones on there now just show you how to screw up the U-joints.
(You don't need a hammer to get them apart, just clamp it in a vise vertically and heat the middle till you see the top side start sliding down then pull it apart, it's that easy.