BLUF: How do I figure out what my truck's gear ratio is?

Hi all. I am new here. I have a 2013 F-150 EcoBoost FX4, 145" wb. I bought my truck about 4 years ago based mostly on a great deal that I couldn't pass up. I never looked into or really considered the gear ratio at the time. The deal was such that it probably wouldn't have mattered much anyways. It has been a daily driver with the very occasional trailer behind it.

Fast forward 4 years.... I am now looking into buying a travel trailer and upgrading wheels and tires. I'm trying to determine a tow rating and configure my new wheels and tires appropriately. Most everywhere I have researched is talking about the gearing. I've since lost my window sticker, had no luck with a VIN decoder (unless someone knows of a good one), and really have no clue how to figure it out (without taking it in). Goes without saying, but my mechanical knowledge is minimal..

I appreciate any help. Thanks

 

Look on the door jamb sticker. What's the AXLE code? It's 2 characters.

 

Your gearing is on the door jamb sticker.

 

The axle code is L9

 

 

Looks like your tow rating is 9600#. Do note that you will run out of payload capacity before you reach that trailer weight.

Weight of the truck with a full tank of fuel, driver, passengers, cargo, and tongue weight of the trailer should not exceed the GVWR on the door jamb sticker.

Factory wheels and tires are okay up to the maximum weight. Aftermarket, unless chosen properly, can actually reduce this rating.