[bsmith0404]

Originally Posted by notanlines

A short story and then a question. A friend is towing a super-lite 5th wheel and has a gasoline engine. He was told by the RV dealer that 11-14 should be his mileage. Now that he has gotten home he and momma did he REAL math and got 8.1 over 2600 miles. What he is sad mostly over is his truck only has a 26 gallon tank. Anybody have any experience with installing an upright auxiliary "gasoline" tank in the bed. Neither of them are thrilled with stopping every 160 miles to refuel. Many thanks to all.

In bed auxiliary gasoline tanks are not authorized for safety reasons. You will not find anyone who manufacturers them. Replacing the original tank with something like a Titan 60 gal is the only option.

Originally Posted by notanlines

Deltadude, I'm wondering why you leave your valve closed at all from your auxiliary tank.....I leave the valve open all the time, I fill the original tank first, then fill the big tank, obviously not opening the fuel cap on the original tank. When the big tank runs out the gauge starts then to move off the full mark towards empty.

Same here, but I don't use the gravity valve, I run mine through a gravity pump with a return line from the stock overflow line to the aux tank. After you run the pump for a few seconds, it will establish a siphon and drain the aux tank into the main as you drive.