I have been having this problem for a while now. Usually (not all the time), when I get up right around 55mph and higher, there is suddenly a sort of like a rumbling or shaking of the car. It seems like the whole car is rumbling, the steering wheel is shaking too. Now, there used to be a loud resonating type of sound that was (i thought) associated with this shaking. So i took it in to the dealer. He said that the problem is a broken whell bearing. He fixed it, and the noise was gone. This shaking and rubling is still occurring now, however. Im not sure what it could be.....it feels almost like it could be one of the front wheels/tires. And like I said, it does not happen every time i get to 55, but more often than not. And when it happens, it seems to happen right at 55mph. Does anyone here know what the problem could be? Thanks.