my truck has a low droning hum when im cruising at about 45 mph but the second I lift my foot from the pedal it's gone.

I put it in first gear and let off the pedal at about 2k rpms and the noise continued to change with the speed of the engine unlike above when I have it in drive.

The pitch of the hum changes directly with the rpm's. The power steering has plenty of fluid. Does anyone have any idea what this might be? The noise is driving me insane. Also when I turn the wheel there is a prominent rubbing sound, but that could be a completely different mountain to climb.

 

Maybe an alternator? My mustang alternator was going bad and did the same thing.