Light grinding noise

#1

02 Outback Sport (Impreza), 75k, auto. Getting a light grinding noise periodically. Sounds like it’s coming from down below. No specific place though.

#2

When?

Cold? Hot? Both?
Idling? In Park? Driving? Braking? Accelerating? Coasting? Turning? Revving?
Can you influence it? Can you make it start, stop, get louder, quieter?
Can you hear it outside car? Only inside?
Please describe periodically.

#3

Cold? Hot? Both?:::: BOTH
Idling? In Park? Driving? Braking? Accelerating? Coasting? Turning? Revving?:::: DRIVING, ACCELERATING, TURNING AND NOT TURNING
Can you influence it? Can you make it start, stop, get louder, quieter?:::: NO
Can you hear it outside car? Only inside? ::: ONLY HAPPENS WHEN DRIVING SO NOT SURE
Please describe periodically.

#4

Have your brakes checked. I’ll bet your grindng the rotor with a worn out pad.

#5

Keep an open ear, this is a Subaru.

The noise may also be from a transfer case/differential or wheel bearing.