Glad that you found the problem and it wasn't anything really serious. I too had an experience using a stethoscope trying to track down a rattling noise. With the scope everything pointed to the front end and after taking the belts off I could still hear just a little of the metal to metal noise. Finally tossed the scope and got under the car and one of the exhaust pipe hangers was loose and it was viberating against the frame.
Ron
