The video below is not my car, but it is making the exact same sound as mine. This only happens with the a/c on, and only in first/reverse when pulling away from a stop. If the car is on a hill/under load the sound is much louder. After I hit 5mph or so the sound is gone. The comments in the video below say a new belt tensioner fixed the problem. However, I have had the belt and tensioner replaced and still have the same sound. So any other ideas on a/c related issues that would cause this?