I have an 06 SR5 doublecab that has a vibration at 62-67 mph. I've had the wheels/tires balanced more than once to ensure that they are balanced, and that the rims are straight. One other thing, I've replaced one of the front half shaft axles with an aftermarket. Could it be possible that this axle isn't balanced? Could it be something else such as the rear driveshaft center bearing? Any help/suggestions are very much appreciated.