My Cherokee has a tendency to 'step out' at the rear end. Wash board roads will make it do this...a sharp crack or pot hole while going around a corner...a bump in the road while braking and turning...a sharp bump while accelerating will all cause that 'chatter' sound and the tail end to wander slightly, and some times more than slightly!

I have new Monroe "oem' type shocks, new Nexen street tread type tires, 235/75/15's inflatedd to proper inflation per owners manual, and all is tight by visual inspection on the back end. Would worn leaf spring bushings be doing this? Most other rubber mounts on this car are in bad shape (see my post a few weeks ago showing the motor mounts), so I am speculating that worn spring bushings would be hard to detect because of the weight on the vehicle, but would let the vehicle's rear suspension 'vibrate, chatter and do that stepping out thing' when hit with sharp bumps. What say all of you?