With the car raised on jack stands/a lift, look on the passenger side of the transmission. It is located in the midsection of the transmission, and you can use a wrench to replace it (can't remember the size). Here's a picture for reference: http://z.about.com/d/autorepair/1/0/D/D/86378842.gif Taken from this page: http://autorepair.about.com/library/images/bl653a-lib.htm
To replace the speed sensor on a 1996 Subaru Outback, first, ensure the vehicle is safely elevated and secure. Locate the speed sensor, which is typically found on the transmission or near the vehicle's speedometer cable. Disconnect the electrical connector and remove the retaining bolt to take out the old sensor. Install the new sensor by reversing the process, ensuring a secure fit, and reconnect the electrical connector.
The 2010 Subaru Outback has a 6-speed manual.
The 2008 Subaru Outback has a 5-speed manual.
The 2012 Subaru Outback has a 6-speed manual.
The 2011 Subaru Outback has a 6-speed manual.
The 2004 Subaru Outback has a 5-speed manual.
The 2013 Subaru Outback has a 6-speed manual.
The 2006 Subaru Outback has a 5-speed manual.
The 2001 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 2005 Subaru Outback has a 5-speed manual.