vibtarion only when pressing gas

i get a virbation/shake when i am on the highway at 60mph+. when i take my foot off the gas the vibration stops even if i am cruising at 65. as soon as i step on the gas again the vibration come back. if i cruise at 55 its smooth. i baught new tires and it didnt solve the problem. i dont think its a bent rim being it only does it while on the gas, thanks for any help, joe

Engine off, raise the rear tires off the ground, put trans in neutral, check for movement in both U joints.

when you say both u-joints, do you mean the two on the rear driveshaft? or front and rear shaft? thanks for the tips. joe

Check the joints on the rear shaft first, then raise the front of the vehicle and check the fronts, (didn't realize you have AWD).