Vibration in the steering and seat when driving at 40 mph or more. Checked and rebalanced the tires, check the drive train U-joints, checked the front end alignment, and checked the CV joints. I did replace one tire and that took some of the shaking out but it still remains. It is not a violent shake but just enough to tell you something is wrong. Had my local garage take a look and they are dumb founded as well. The truck runs like a million buck but the shaking is driving me nutsoid. Can you tell me something?
Why was the one tire replaced? What was wrong with it? How old are the other 3 tires? When you say the tires were checked, what exactly was looked at? Did they check for sidewall bulges or tread cupping?
Is there a noise associated with this shaking?
Put the front end up on jack stands and jiggle the wheels with your hands at the top and bottom. Do they move? How much? Now spin them and see if there’s a wobble. While you’re at it, check all the lugnuts, and retorque them all to factory specs.