I just came back from the dealer and they are going to order two new rear shocks under warranty to fix this intermitent noise in the rear of the car,also had a courtesy oil change using my own Penzoil ultra platinim,also as a courtesy they replaced the rear differential fluid at no cost,based on the work order it took two quarts which was a bit surprised,also had some oil seepage on the rear valve cover which was cleaned up,also updated the navi unit,cluster. Z