I bought my Compass in March, 2018 and noticed the same thing immediately. I just thought it was kind of a really "cool" noise - fun! Now, as I read your post and am facing issues with the engine which was replaced only a few months ago due to excessive burning of oil, I realize that the issues I am facing now are with the engine and throttle. It is now 1/2022. It is not a good time to look for a new vehicle, and I am a die hard manual transmission kind of driver as I am mostly on back roads, and have always enjoyed driving. I loved the Compass. It is apparently one of the last with a manual transmission. Always wished it was, at least, a little bigger and had heated seats, heated steering wheel - all weather package. VERY disappointed to let it go as I am not finding anything I really am excited about, but it has had A LOT of issues all along. I appreciate reading your comments because I know this is something very real - not "just me!" I am wondering what happened to your vehicle as you went along. Thank You! -I have a 2019 compass and when I'm decelerating when vehicle gets to 40kmh it makes loud humming noise so far dealer has replaced rear differential and front transfer case and issue is still present. Dealer says its normal because all the other vehicles on lot makes similar noise. Does anyone have similar issues?