I have a 2014 Rouge that I recently got. When I'm driving and get to roughly about 30mph, then start to accelerate, it makes this real faint and subtle sound. To me the best way to describe the sound is as if the tornado siren is going off. Once I stop accelerating the sound stops, but if I accelerate again it starts right back up. The car doesn't shake, there are no lights on the dashboard and the oil, fluids and filter were all recently serviced. The previous owner states that they never heard any sounds, but it was being loaned to a friend of theirs for a couple months before I acquired it, so they didn't drive it again before I got it. Any idea on what it might be? Your help is greatly appreciated in advance!