Vibration at different speeds.. Dealer road force balanced and the speed at which it vibrates changed. Dealer refuses to do anything else, simply ignores requests. Dealer road test technician agreed on severity of vibration and said the next step was to change the tires because, as he put it, Goodyear are sh@t tires. Shop manager was upset with the technician and told me it was not going to happen and refused further requests for service. I wish I could go back and not buy the truck.