Weave, As you know, we have the International 7400 with DT530 Allison 6-speed. This truck has 5.63 rear-end gears. While we love the way the truck accelerates, the fuel mileage is horrendous. Our last truck was an FL-70 (8.3 cummins, 7-speed), this truck got app. 10 to 11 mpg. Our International...