When I press on the gas pedal to accelerate, I hear a squeak/squeal sound coming from under the truck. When I left off the gas pedal it stops until I press it again. The sound is constant when accelerating or cruising but stops when I press the gas pedal to the floor to accelerate quicker than normal and if I let off the gas pedal entirely and just coast. I'm 100% certain it's not a belt squeal. Anybody got any ideas?