[onewhippedpuppy]

Originally Posted by rfuerst911sc

To be clear I haven't used it yet . But yes it gravity feeds into the factory tank . The auxiliary tank has a simple ball valve on the drivers side . From that valve is a rubber 3/8 hose that goes thru the steel bed top and down to the main tank filler neck . I purchased a " kit " made specifically for this . The main piece of the kit is a tee that goes into the main tank filler neck . At the top of the tee is a welded nut .

A special fitting screws into that nut , it has a rollover safety ball inside of it to stop flow if the truck rolls over , it also supposedly will float up if the filler neck gets full to stop overflow . It also has an elbow at the top of the fitting that the rubber hose slips over . So in theory when the driver decides fuel is needed you open the valve . The vented auxiliary tank gravity feeds into the main tanks filler neck and into the main tank .

Unknowns: I don't know the feed flow rate vs the trucks consumption . Obviously a 50 gallon tank feeding into a 32 gallon tank has a potential for overflow . So I will have to experiment a little bit to understand when to open the valve and when to close it . Example- when towing our 5th wheel camper I get 12 - 13 mpg . So do I open the valve when main tank is at half ? Or do I wait until it's a quarter ? That kind of thing .

That’s pretty cool, I like the idea. Lots of farm trucks around here have big aux tanks but they normally have a hand pump so they can refuel farm equipment.