Having a problem that started today. Don't know where to begin. When stopped at a light the rear of the car feels like it's grinding/humming. It goes away if I put it in neutral or start to move in gear. I can still hear/feel it while driving but not as bad. I didn't go over 35 mph back home to avoid damaging anything. Any ideas? Trans? Rear end? The car was running a little hot. Could warm fluid be causing these symptoms? I parked it at home and while sitting in the driveway I went through the gears and only felt the straining whirring sound in drive gears, not neutral or park.