So I'm trying to narrow down a noise from 40-60 in my forester. Thought it was front wheel bearings, changed both... Still there. Next thought it was a drive shaft carrier bearing....... swapped with good one. Noise still there. My last things it could be are the Rear diff, rear wheel bearings or trans. There is a slight noise that starts around 20 and increases in pitch all the way up, then there is a loud noise on accel from 40-60 and then it makes the same noise but less noticeable on decel from 45-40. Looking to borrow/buy a rear 4.11 diff to try and eliminate that as a possibility before i buy a trans or sway rear bearings too. Car is a 2001 forester 5sp with 67k miles