The transmission has nothing to do with the 4wd system and there is nothing to convert. Just install the transmission and you will be good to go if you have the right transmission.
The 2009 Dodge Durango has rear wheel drive.
The 2003 Dodge Durango has rear wheel drive.
The 2012 Dodge Durango has rear wheel drive.
The 2011 Dodge Durango has rear wheel drive.
The 2007 Dodge Durango has rear wheel drive.
The 2005 Dodge Durango has rear wheel drive.
The 2013 Dodge Durango has rear wheel drive.
The 2001 Dodge Durango has rear wheel drive.
The 2008 Dodge Durango has rear wheel drive.
The 2006 Dodge Durango has rear wheel drive.
The 2002 Dodge Durango has rear wheel drive.
The 2014 Dodge Durango has rear wheel drive.