Hi, I had a similar problem with our 40' 2006 Monterey. It was a real pain to drive as it would move around whenever I lifted off the throttle, or hit the brakes. 8 new shocks and new tires didn't help. when I brought it in for a front and rear alignment, the shop found worn bushings on the rear torque arms. Turned out the real culprit was the hole in the mounting plate. Had to weld new plates over the original holes.... drives like a different coach. Good luck, Don