I know I'm bringing back a dead thread but for future reference, I figured I would answer. To use the 904 or the 999 you'll have to find a 2wd trans with a 360 converter. You then swap out the tail shaft of the 2wd and your Jeep's 4x4 shaft. It's not a hard procedure. The torqueflight is a very simple trans. In fact I just rebuilt my 727 for 120 bucks in my 84 ram. While you have your 904 out you can also install the 999 bands and beef it up. I'm currently trying to figure out the engine mounts for my build in my 85.