Seats popping noise when weight shifts (start,stop,etc.)first attempt was to replace the seat back. second was to replace the entire seat minus the cover. third time in the service manager wanted to contact the area gm manager for direction. the gm area manager told the service manager to make no repair and direct me to call gm. this truck also has been in for service to the brake rotors to be re surfaced with only 4,600 miles on the truck. the transmission has re calibrated two times one for the lock-up torque converter,and once for a hard shift from first to second gear. the truck has a harder shift now than before. *jb