One correction, in 2003 (2004 and prior), the F550 had the Dana S135 axle not the S110, hence the apparent reduction in size from the massive 14.38" ring gear of the S135 to the more "reasonable" 11.8" ring gear of the 2005 S110.
Last edited by n578md; 01-22-2005 at 03:45 AM.