My truck shakes at high speeds, mostly over 70mph to the point my seat belt has locked up. I feel it in the body and bed. Steering no shaking. Just noticing It tends to shake more when 1/2 tank of fuel. I have had 3 different mechanics look at it. I have replaced rear shocks, u-joints and a track bar added in the rear end ( track bar helped)
More likely a tire problem. You have had the truck three years, now there is a problem. What has happened?
I failed to mention I replaced the tires too.
Are the new tires LT rather than P tires? They are rougher riding.
Have shop check to see if new tires are out of round, extremely rare but possible.
Have tires rotated front to rear, see if vibration changes.
Road force balance tires.
I had a car that was sensitive to lug nut torque, if done with a pneumatic tool car would shake.
Have you checked for a bent axle flange?
With all that work, you must have gotten a 4 wheel alignment, correct?
I have not. Thank you for the advise
I did. I have had several shops do a balance on all four tires too.