Have vibration in front floor of truck. Can feel it in left foot starts at around 30/40mph. Have changed tires and rebalanced. Front end check out O. K. as well as ball joints. Replaced front shocks as well as rear no help. Have had Dodge dealer check out all they say is they can not find anything wrong U-joints are good. This a Automatic with 28,000 miles anyone have any similar problems and found a solution for it? Thanks