Bought an 01 Gran as a DD. Had many CJ, Waggy and XJ but this is my first Gran. Was in too great shape with 120K to pass up but had rear suspension issue. Replaced rear axle upper control arm with new including ball joint as it was falling apart. Also replaced all shocks (rears were self destructing). Alignment is slightly off but otherwise front end is tight however the car still rides slightly wiggly in the back. Is that just the nature of these? I can't find any other visible issues.

 

The only other thing I can think of is rear swaybar links. The rear shocks on my '00 WJ are still working fine even though the upper rod covers are just about gone. Mine has 167K on the original parts and rides rock solid. The shocks are Monroe, replaced by the previous owner. I'm amazed at how solid this 15 year old jeep rides.

 

The rear link suspension will feel a little different from a leaf sprung suspension. Make sure all of the bushings on the lower arms are ok.

 

I remember back in the day I had a 70 Buick 455 GS that had coil rear and it was sloppy which was kinda hairy with that much power.