I don't know what are you think it is It doesn't seem to change with the change in the reciprocating mass of the engine transmission and drive axles so it seems kind of steady like possibly a wheel bearing air flowing up through the fenders God knows does it do it when you're sitting still what happens if you put the wheels up off the ground on jack stands or the car up on jack stands at the jacking points and the wheels turning going nowhere car running You still have the noise while the car's not going down the road but the tires are turning by the transmission and car running You still have the noise aha.. ?