Have a 2009 Legacy NA with 5MT. Has a whine under acceleration coming from front of car. Pitch of the sound increases with speed. Noise is present but noticeably quieter coasting. Noise does not change when turning. Sounds like it is coming from front center, but can't be positive (could be more on passenger side).
No, it is not an exhaust leak, vacuum hose, alternator bearing, etc.
First thought was CV - but sound doesn't change when turning, no clunk,clunk,clunk
Second thought was wheel bearing - but sound gets quieter when not accelerating (ie 30 mph and accelerating to 40 is louder than coasting from 40 down to 30).
Lube level in diff is ok.
Any thoughts are appreciated.