I have a stock 1991 XJ 4 wheel drive 4.0 5 speed. when I go over a speed bump slowly i sometimes hear a "Clunk" sound. and sometimes when I bump a parking curb I hear it. sometimes it doesn't do it, some times it does. also in the morning when I go to work, I back straight up, and when I turn to the right to line up with the driveway, I hear a clunk, some times. I have changed the shocks, wheel bearing hubs, all the control arms except the top center one ( it is so tight I can't get it loose) tie rod ends, ball joints and even changed one of the U-Joints in the drive shaft, and the sway bar bushings. I have had several mechanics put the car on the lift and look at it, they say everything looks good. It can't be all ok because I still hear the clunk from time to time. I have NOT changed the U-Joints in the axle's yet. could that be the problem ? I have rocked the truck back and forth and looked at the joints and they look ok, but maybe under a load ??? could they be bad causing the clunk sound ? normal driving is perfect and in 4 wheel drive everything works, but even driving over a bumpy road you can hear the clunk coming from the front....any one ever have this ? I hope someone can shed a little light on this for me.