[Dusters]

I bought an aux tank from Camping world and they installed it and tapped into the filler neck with a shutoff valve at the base of the tank/bed. The Chevy (8ft bed) has 37 gallons while towing goes close to empty around 325. Usually, 350 is the trip distance. The aux tank is 30 gallons and is about 10" wide and height to the top of the bed, losing about 12" of bed space. I fill both tanks full at the beginning of a trip (about $200 now) and close off the aux tank from the main tank. When I get to about 250 miles on the trip, I open the aux manually and let fuel trickle into the main tank. When I stop for the evening and setup, I cutoff the aux tank leaving the main tank full and refill the aux only. At CW the tank was about $600 and additional $300 for install and tubing parts. I keep the tank empty when not towing, due to diesel crud and weight factors. The filler is hole is on driver's side next to the main tank, so it's easy to move between tanks. Hope that helps.