I am pretty sure the dealer can do it or you can but a NGS scan tool or something similar.
i paid $200 retail should be about $250
you have to have a special height sensor tool that can adjust it for you, go to the local parts store and see if they sell it, or if your lucky enough to have a friend that has one.
The height of the 2013 Lincoln Navigator is 6 ft. 6.3 in. (78.3 in.).
The height of the 2005 Lincoln Navigator is 6 ft. 5.8 in. (77.8 in.).
The height of the 2001 Lincoln Navigator is 6 ft. 3.2 in. (75.2 in.).
The height of the 2010 Lincoln Navigator is 6 ft. 6.3 in. (78.3 in.).
The height of the 2007 Lincoln Navigator is 6 ft. 6.3 in. (78.3 in.).
The height of the 2003 Lincoln Navigator is 6 ft. 5.8 in. (77.8 in.).
The height of the 2012 Lincoln Navigator is 6 ft. 6.3 in. (78.3 in.).
The height of the 2004 Lincoln Navigator is 6 ft. 5.8 in. (77.8 in.).
The height of the 2009 Lincoln Navigator is 6 ft. 6.3 in. (78.3 in.).
The height of the 2002 Lincoln Navigator is 6 ft. 3.2 in. (75.2 in.).