Over the past month I've started noticing a distinctly loud humming noise coming from the rear passenger side of my Focus. Its a 2012 Focus Titanium Hatchback with the sports suspension for context.
I originally thought based on searches online and this forum that it could be a wheel bearing. However in talking with one of my buddies he said that a wheel bearing would be a much higher pitched sound. The sounds is rather low and really kicks in around ~30mph and gradually gets a little higher as I hit the freeway.
I then thought it was maybe tires being low so I ensured they were filled all the way. No dice.
I also just put my winter tires on over the weekend and the noise is a little lower pitched, but still very present.
I thought maybe something with the muffler but I feel like if that was the case the pitch would follow the RPM's rather than speed? I gave it a visual inspection when I changed the tires and it looks fine to me.
I do have a lot of the noisy transmission and grinding problems others have mentioned and have tried to get this fixed based on the FSA letter I recieved, but the dealership around here (metro Detroit) are booked until Feb '15 fixing this problem. I wonder if it is something related to the trans?
Any ideas you may have would be helpful. Thanks!