I'm not that familiar with the Cherokee, but it it's anything like my CJ, you'll have to pull the driver's side hub apart and remove the driver's side half-shaft.

You can replace the u-joint yourself, but I find it easier just to take it to the auto parts store where I get the u-joint and have them press the old one out and the new one in. They charge 15-20 bucks, and it's worth it to me.

1977 CJ-7, fiberglass body, AMC 360 w/ headers, DUI ignition, Edelbrock intake and Holley 4150 carb, TF999, Dana 300, 4.56 gears lockers, York air comp, 4" susp lift, 2" body lift, BFG 35" M-T tires, Megashifter, AGR pump & box, REP8000 winch.