Hi
Have an impreza base model that is humming from the back. Doesnt seem to be getting worse. Been this way since I bought it used so I don't know the full history. Loudest at 40-50mph. Quieter above and below those speeds. Turning doesn't change the consistency or sound. It's a steady humming, not a pulsing sound.
Rear diff fluid and atf fluid changed (genuine Subaru fluids and gear oil) with no improvement or worsening of the sound. Car has 105k miles.
Putting the automatic in neutral while coasting doesn't change the sound.
No uneven wear in the tires.
Any idea?
Thanks.