I have a 2002 FL century twin screw, N14 cummins, 10 spd autoshift. it weighs 24000 with 200 gallons of fuel, 2 drivers, and a tripak hangin on the side. I LOVE this truck! It leaks nothing, it burns 1/2 gallon of oil in 15000 miles, gets an average of 9.12 mpg ( I have gotten as much as 10.46 )...