Find Cheaper Diesel? Here's Where to Put It
The toolbox sits atop the auxilary tank, and the filler neck for the tank sits inside the toolbox lid, locked up and out of the way. Unlike "read the fuel gauge and remember to flip the switch" style tanks, however, this fuel tank system automatically senses the level of your truck's OEM tank and transfers fuel out of the "toolbox" and into your OEM tank. You don't need to think about it.
The Transfer Flow system is designed for domestic pickups over a fairly broad range of model years. While the tank system is retail priced at just under $900, you'll need to add anywhere between $16 to $27 additional for the appropriate filler neck adapter. Check out all the details on the Transfer Flow web site.