I currently have a 2017 Ford XLT FX4 super crew with the 23 gallon gas tank and want to switch it to a 36 gallon gas tank. How hard would that be to accomplish and what do you think the cost would be to purchase such a tank?

 

I don't know... but I do have that tank, and I understand that it's a two chambered thing with some kind of siphon that empties one into the other. I think it's got some digital stuff involved with it.

This info comes from some reading I did way back after I got the truck. It's a 2015. Other's expertise migh supersede mine.

 

Did mine 7 months ago same make model as yours, cost me right around 700 bucks, you will need pump assembly, 36 gallon tank and off road fx4 tank shield, and forscan to change it from 23 gallon to 36 gallon tank.