At 1500-1700 RPMs (60-65 mph) AND 1100-1200 (35-38 mph) I hear a constant whistling-whirring noise from up front. (belt, rotor, u-joint, etc maybe). It goes away when I take my foot off the gas. Dealer thought it was a tire but no luck on that. Any thoughts? I recently bought it used with 27K and it's otherwise in great shape. I don't think the dealer is too enthused about diagnosing this one so any suggestions would be most appreciated. Thank you.