Just a couple quick ideas. Loosen all the nuts and bolts at the suspension tie points, rear shackles, front control arms, front attachment of the rear spring. Set the car back on the ground and bounce it from all corners. Take a look and see if it is better or fixed. If it is okay then tighten the nuts and bolts that were loosened " while it is still on the ground" . If this does it the bushings were inadvertantly pre loaded and that can cause this to happen as well as premature failure of those components. Been there - done that!
Hope that does it
Terry