Gosh, could be lots of things. ANY noise at all in park or neutral? How about when you are idling in drive and load the brakes? A video with some GOOD audio might help.
Nope. No noise in park or netrual. The noise starts when the cars starts moving. Only recently did the brakes start killing the motor, when pressed. That is a seperate issue. As far as the noise, it sounds like a loose driveshaft wobbling, but we know for a fact that it's not the driveshaft.
