Found out my truck was supposed to come with this "capless fuel tank
funnel" but it didn't. Missing in action. I just ordered on on
Amazon because they are inexpensive.

There are two flappers that must pushed open in order to
add fuel or anything to the gas tank. A portable gas jug's nozzle won't
penetrate both nor will any bottled gas additive that people may swear by.

I was reading why this capless design is being included on newer
vehicles. The reasons are varied, some not making any sense to me,
but not worth listing. They would start a huge debate. :-)



Anyway, it sorta looks like this:

https://images-na.ssl-images-amazon.com/images/I/51pkagV7uML._SL1000_.jpg