So when I'm driving I'm hearing a humming noise coming from what sounds like the drivers front. Not as much when I'm accelerating but when I let off the gas. I had both CV's replaced roughly a year ago and I looked at them both and the boots looked good, no play in them that I could tell. Nothing is touching the tires. Transmission shifts great and quick and doesn't seem to be louder faster I go. Any ideas what could be making the sound?