91 gmc sierra with 305 When I put the truck into gear I hear a faint chirping sound and when I accelerate a little it gets pretty loud. In park or neutral the noise is really faint but doesnt get louder as I accelerate it has to be in gear. It is loud with a little acceleration and gets quieter with more acceleration. The noise is coming from the front near the crank pulley. I started it without the serpentine belt and it still makes the noise. Thanks for any help!