...so also appearing on the long list of 'needs' was a way to fill up the gas tanks (x2)...but there isn't a lot of real estate on the bedside so I had (wanted...ok "needed") to devise a way to easily fill (and vent) two tanks with one filler neck, whilst also incorporating a way to flow fuel from one tank into the other via the fancy filler neck...and this is how I'm intending to do it; keyword = "valves".

Here's the land mass I have to work with...and it ain't a lot -


I picked up a pair of manual fuel-proof valves, IIRC with Viton seals and stainless hardware, that with a simple flip of a lever will allow me to close off one filler hose and open the other...and vice versa. I really wanted to utilize the fuel fill neck in the stock location (no need to turn the truck around to fill the other tank), but needed two outputs, so I grafted another OE output tube onto the original, then added the valve ends so they bolt on; then added a fresh 3/4" port for the main vent and an NPT port for the eventual aux fuel fill inlet. Close the auxiliary (upper) valve and fuel flows into the main (lower) tank...then when the tank(s) fill up the nozzle should (hopefully/presumably) shut itself off, then I'll close the main valve and open the aux, then hit the nozzle again and fuel will fill up the lower neck and then 'should' flow into the auxiliary tank. When both are full I'll close the aux valve, open the main valve (or I suppose I could leave it closed to prevent fuel from flowing out off-roading)...and motor on - at least that's what I'm hoping will happen 👍

For comparison, here's what the original looks like-


Here's the overall main filler neck - Kinda reminds me of something out of a KC-135...and hey I'm retired Air Force so extra kewl points -




Installed; naturally I'll have a flexible 'shield' to keep debris/mud/rain from impacting the plumbing -


Filling the main tank: main valve open (lever in-line)/aux valve closed (90*)-


...and the opposite to fill the aux tank -


Will prolly haul the truck (or clandestinely drive it) to the nearest gas station to test it all out...