Team, When I'm driving in 1st, or 2nd gear at about 3000rpm I hear a strange, sort of oscillating noise in the engine compartment. It sounds like a low pitched vibration, almost like my front license plate, or maybe that heat shield next to my battery, is vibrating loudly, but just at a specific frequency (2800-3000 rpm). It's sort of a rrroonnngg-rrroonnngg-rrroonnngg, but only within that rpm range. Clutch never slips, never pops out of gear. Car has a fairly gentle 115k miles with no clutch replacement. Ideas? Thanks. Dennis