New Ram/Cummins vs GM/Duramax on the IKE

Weel seeing how the engines are about the same and the biggest difference is the GM had the 10 speed and 3.42 (Tall gears), and the Ram had the Aisin and 4.10's (Low gears), I would say the 10 speed in a GM 3500 DRW will get better mileage, depending on engine RPMs. I now turn about 1,500 with the Aisin and 3.73's at 60 mph, our old 2001 turned 1,800 RPMs at 60 mph with 3.55's, so final OD is taller.