The mileage is a mixture of both hand calc and overhead, they are usually within 1 mpg or so and that's close enough for me. Stock size tires, mileage has always been poor compared to past and present trucks but the pulling power has been phenominal.
Thanks for the welcome! Took out the fan looking thing, fuel filter is fresh, air filter is semi fresh. Mileage still @ 12.7 empty. Mileage seemed to always be this way...80k now. Pulls better than all the diesels that came before so I'm not complaining...just wish the mileage was a bit better.
2006 LBZ, Allison Crew Cab 3500 Dually, 4:10 gears 4x4-all stock. Wifes truck, pulls a 14k 5th wheel horse trailer EXTREMELY WELL- no complaints there. Mileage seems low, especially when empty. 8-11 mpg when towning ( I'm thinking not bad, most in hilly PA.) Empty is 12.7 average rural and...