I have a 2002 3500 One ton 4x4 dually, cab and chassis with dual fuel tanks. To fuel the truck I never fuel up while truck is running and fill the front tank first. I do this to eliminate messing up the fuel guage and I under stand the rear tank pumps fuel to the front tank. Twice now my gauge read 1/2 to 3/4 and the truck runs out of fuel (which I discovered the hard way) on the front tank. When this happens is there any way to make the rear tank pump fuel manualy to the front or rest the pump. Calling for fuel on the hiway is no picnic. I use my truck for work in the oil and gas industry and we can be a long way from any services. It has done this twice now in about 9 months and the dealer after getting towed becouse I had lots of fuel but not in the front tank. It rest after I fueled the truck up. Thank you. PS. I will be asking my service manger when I get time off.