Dean if your thrust arms are original I'd look into getting those looked at, the arms should be tight with no play, if they are worn they will have play and flex in the bushing area.

You can either have just the bushings replaced or replace the whole arm as I did, I also replaced the ball joints on the arm too.

Rick,
Thank you for the response. I wi look into the stack of repair orders from the previous owner to see if that was ever replaced. I also read somewhere that the nuts/ should be tighten when the wheels are on the ground. I tighten all the bolts while the X was on the lift. I did at my friend's shop. I guess I should have spend more time looking thru those items. Lesson learned.

You may have prematurely worn the bushing if that is the case and that could be your problem, yes the bushings have to be torqued with wheels on the ground for the control arms that bolt to the frame. Good luck dean!