I had been told one could test with this method,, also here is another guy that feels the same way. per his quote "That sounds like a good plan. Additionally, I would drive the car at the speed where it vibrates and put the transmission in neutral. If the vibration goes away then it's in the drivetrain. Try to determine if the vibration changes when you are on the throttle and when you're off. Rev the engine in neutral to see if you can duplicate it (while driving down the road)."
