Hi, I have a 2003 g35 sedan auto with 84,000 miles. I have a strong humming sound coming from the rear of the car that the faster I drive , the more it sounds. I tough it was a wheel bearing but when I took it to a mechanic today he told me that the sound is from the differential. He lifted it and began to spin both wheels but could not found a problem with the bearings. So he said my differential could be bad.

The thing is I though it was the right bearing because when im driving if I turn the car to the left, the sound improves, but if I turn to the right, the sound almost disappear completely. I think I am going to look for a second opinion, fingers crossed. What do you guys think??

 

Not too sure are on this one, but for some more info your car has an open diff, so you really shouldn't have any mechanical noise coming from it.

Maybe change the diff fluid and see if it changes.