when i floor it from a dig at about 4k a loud whine similar to the sound of a supercharger comes from the engine and if i keep on flooring it the whine will continue through all of the gears but if i let off of the gas it stops. if anyone knows what this is please let me know. my truck has been to 3 different dealerships and they cannot figure out what causes the noise. the only thing they know is that when the serpentine belt has been removed it doesnt make the noise. the idler pulley, tensioner, and a/c compressor has been replaced and it still makes the noise.

 

well then, what's left? ALternator, water pump, anything else in there?

 

It's probably the belt itself.
The consensus seems to be that
the Goodyear Gatorback belt is the quietest.

 

How about the power steering pump?