Consider the possibility of a bad differential or wheel bearing. Is it a grindey scrapey noise? If so suspect wheel bearing or differential.
If car is lifted off the ground and trans in neutral, frmly grasp each tire one at a time and rotate. If a slight vibration is felt, replace that bearing. This vibration is very slight so pay attention, okay? If not show any vibration, expect a differential (or possibly but not likely transmission) problem.
The 2013 Subaru Outback has a 6-speed manual.
The 2005 Subaru Outback has a 5-speed manual.
The 2011 Subaru Outback has a 6-speed manual.
The 2014 Subaru Outback has a 6-speed manual.
The 2001 Subaru Outback has a 5-speed manual.
The 2002 Subaru Outback has a 5-speed manual.
The 2004 Subaru Outback has a 5-speed manual.
The 2008 Subaru Outback has a 5-speed manual.
The 2006 Subaru Outback has a 5-speed manual.
The 2009 Subaru Outback has a 5-speed manual.
The 2007 Subaru Outback has a 5-speed manual.
The 2012 Subaru Outback has a 6-speed manual.