just took my obs chevy to the dealer for recall and body work ... they gave me a nice rental truck ... 2wd 3500, ally auto, dmax diesel, dump bed, 2005, etc.

question is, it has dual fuel tanks, can anyone explain how they work, cuz i cannot find anyway to switch between the two... ?? any help ? or how does it work

jake

In most cases the second tank has a pump on it that fills the first tank as it's level goes down.

Big free flowing pipe with vent fills the back from the front. During driving and after front tank reaches certain level, the back pumps into the front.

GM didn't want people having to worry about switching, so they came up with that slick system. basically 50 gallons on board with one pickup and one level sensor. Little cheaper than a switch and transfer valve....and a heck of a lot more convienent.