1990 Ford F150 V8 Four Wheel Drive Automatic 84454 miles
When I'm driving, a buzzing/humming sound comes from the left/front wheel well. As the speed of the vehicle increases, the rate at which the sound occurs also increases. The sound stops when I'm at a complete stop. After driving for some time, the hub to the 4X4 assembly is burning hot on that side. When I engage the auto 4 wheel drive and go through all the gears, the sound still persists. Suggestions would be most appreciated.