Hey, I just bought a new 2010 Forester and I was wondering if this is normal. I notice this odd sound with the windows rolled down coming from the engine. It only seems to occur shortly after I have shifted and have begun to accelerate or slow down, mostly during the lower gears, 1-3 and while running at lower-midrange speeds. I will hear a soft "switch" sound and the engine humms at a slightly higher pitch while running at the same speed. As a result notice 2 very distinct sound pitches from the engine.