2004 Forester XT Premium 4EAT w/ 4WD on demand
I have a humming coming from the car when drive at 50mph, kinda has a doppler effect. I noticed it after I changed my oil back to 5w30 instead of 5w40. Anyone have any idea where I should look. I thought it might be the oil (I keep an eye on that though), gas filter or tranny/gear fluid. And it doesnt cycle fast enough to be a tire.