GREEN16

Not gonna be worth the money and effort IMO. 3.73 to 4.11 is a relatively negligible change, you'll get going a hair easier maybe but you'll turn more RPM on the highway. I guess it depends what your priorities are with the truck.

Now if you were going from 3.31 to 4.11, that's another story...

marshallr

3.73 gearing in a 2013 would be quite rare. Depending on the engine, 3.55's are usually with 5.0's. Most 3.5 EB's have 3.31's

There is an axle code on the sticker on the door or door jamb. Chart to figure out what axle is on it if you scroll down 3-4 pages here.

http://www.ford.com/resources/ford/g...rv&tt_f150.pdf