you dont have to go back stock. any 80w or 90w will be fine. gear oil is gear oil. just tell the parts hose you need 80w 90, and you will be fine.
The 2013 Ford F-450-Super-DUTY has 68.0 in. of front shoulder room.
The 2012 Ford F-450-Super-DUTY has 68.0 in. of front shoulder room.
The 2015 Ford F-450-Super-DUTY has 68.0 in. of front shoulder room.
The 2012 Ford F-450-Super-DUTY has 67.6 in. of front hip room.
The 2008 Ford F-450-Super-DUTY has 68.0 in. of front shoulder room.
The 2013 Ford F-450-Super-DUTY has 41.1 in. of front leg room.
The 2011 Ford F-450-Super-DUTY has 41.1 in. of front leg room.
The 2009 Ford F-450-Super-DUTY has 67.6 in. of front hip room.
The 2009 Ford F-450-Super-DUTY has 68.0 in. of front shoulder room.
The 2014 Ford F-450-Super-DUTY has 67.6 in. of front hip room.
The 2008 Ford F-450-Super-DUTY has 41.0 in. of front leg room.
The 2010 Ford F-450-Super-DUTY has 68.0 in. of front shoulder room.