That is excellent because I have yet to get over 12mpg under any driving conditions in my 03 Screw FX4 3.73 with the 2V 5.4L.

 

I have the 3.55 and plan on changing it to the 3.73 once I've researched the parts to order. This truck is just too heavy for the 3.55 to offer the responsiveness it should have with the 18 inch wheels. Heck, I'm even thinking 3.90 is anyone sells the gearset.