What is casuing my 01 Santa Fe to vibrate bad around 40 MPH
 

Hi all, I have an 01 Santa Fe AWD V6 and for the last year or so when I drive in the city or backroads, once I hit 38-42 MPH the car will start to vibrate very bad, as soon as I let off the gas pedal some or speed up some it goes away. My brother & my husband both think that the car is trying to go into overdrive, first we thought the tires, got all new tires and everything and it still does it. It;s very aggravating when it does happen, it vibrates the whole car. Does anyone know what would cause this and if my brother & husband are right about the overdrive thing how can I get that fixed ?

Thanks,

Robin in Cincinnati, OH

it could be a warped rotor too. Same principle as an out of balance tire, but no way to balance it. Rotors can become warped if people don't tighten lugnuts consistently. It's why I always insist (as do most reputable tire places) that lug nuts be hand tightened with a torque wrench. Thats just a thought.