the noise seems to come from underneath the front passenger/transmission area and only occurs when the vehicle is in gear on acceleration. sounds like a rotation noise. the motor is a 351 and the tranny is automatic w/ overdrive. there's a couple other modules/whatever in the vicinity where the noise is coming from but i don't know what they are or their function. can't pinpoint the source as the only time noise occurs is when the vehicle is in motion. help!

I had an exhaust manifold gasket blow on the pass side at 165K - only heard it under acceleration and it sounded like a clicking noise. Once I removed the consul and drove a block I could tell it was an exhaust issue.

Take it to a mechanic that specializes in F 150's. Chances are they seen or heard of it before. Sounds llike a driveline tick. Are the U-joints in good shape? Get underneath and grab hold of the driveline, u joints, exhaust parts and see if you can find something loose.