Combining aerodynamic body, efficient rear axles, and drivetrain that employs advanced downspeeding, ProStar ES maximizes fuel efficiency. Truck offers Eaton Cummings SmartAdvantage™ powertrain which pairs Cummins ISX15 with Eaton Fuller Advantage™ automated transmission, as well as Navistar's SCR-based 13 L engine and Eaton Fuller Advantage™ automated transmission. ProStar® ES also includes 3-year subscription to OnCommand Connection, Navistar's predictive diagnostic system.