It started about 3 days ago....a soft "buzzing" noise from the rear of the car. I first thought I had picked up a rock on my tire but after checking the tread, no rocks. This buzz can be heard above 50 mph, but must be too soft (or non-existant) at lower speeds. It's a constant buzzing noise that does not change pitch or volume if I shift into neutral and coast, so I know its not the engine or transmission. It does get higher in pitch as I speed up from 50 mph, but not really louder (the road noise may mask an increase in volume though). Must be either in the drive train, rear end, wheels or tires. It definitely is coming from the rear of the car as I put my rear seat down and can hear it coming thru the truck space.

Any ideas what the noise is coming from?

 

could it be the bearing in one of your wheels?

 

im having the same problems as after i put on my winter tires