About 2 months back I started hearing a humming while I was driving. I thought it was road noise because I had not long rotated the tires. About 3 weeks ago I started hearing a slight grinding sound coming from the driver side front wheel area. So I took the vehicle to my mechanic and on a quick test drive he said it sounds like the wheel bearing so we changed it, however the sound was still there. So I took it back and they did a complete check and concluded that its coming from the transfer case. From my observation it really only makes the noise when I'm driving and I release the gas pedal and rolls freely. I just bought a brand new OEM transfer case and I hope that this is the solution. Anyone have any other ideas?