I have a 2004 F150 supercrew with 59000 miles witha vibration in the steering wheel, very high pitch, new tires, trued and balanced, new drive shaft, still have the vibration at 15 to 30 mph, the only mods to the truck is lowered to level in the rear to match the front. Is this truck susposed to have a vibration dampener on the left rear frame. TKS