We have a 2018 Chateau on a 2017 F550 chassis. We were told that the fuel is always pulled from the front tank and that the pump in the back tank simply pumps fuel to the front tank. I’ve not watched the gauges close enough to verify but I do know that the back tank is always the first to go empty and the level in the front tank always seems to stay full until after the back tank goes empty.
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