I have a vibration starting at 45mph. Its worse from 45 to 50 then smooths out past that. I can some what feel it at 75mph. I can feel it in my butt and gas peddle, sometimes in just the wheel at 35mph no higher or lower then again at 45mph. I replaced the u-joints saturday and no difference. Any ideas on what it could be? Tires? Wheel weights?:dunno:. Could this be the start of the Death Wobble?