Eaton Corp. and Navistar International Corp. have co-developed a new family of fuel-efficient transmissions for heavy trucks, and will jointly release the systems. The UltraShiftPLUS transmissions, designed for Navistar diesel trucks, are 16-speed direct-drive automated mechanical transmissions with a small (17%) step between gears to optimize time in a diesel engine’s most efficient RPM zone, and help reduce fuel consumption.

“The direct-drive design also boosts the efficiency of the transmission gear train, to further promote excellent fuel consumption,” stated Shane Groner, North America product planning manager for Eaton’s Commercial Vehicle Transmission Division. “All of the other features and benefits of the UltraShift PLUS are included in this newest addition to our lineup.”

Trucks that have tested the new transmissions have demonstrated fuel-economy improvements in the 2-4% range.

Production is scheduled to begin in April, and the first commercial application will be the UltraShift PLUS LSE (linehaul small-step efficiency) for Navistar’s MaxxForce 13L SCR engines on the International brand Class 8 trucks. Subsequently, it will be available with Cummins ISX15 engines.

”Fuel economy has been the cornerstone of the International ProStar (trucks), and with the collaboration with Eaton on the 16-speed direct-drive automated transmission we’re able to deliver even more tangible fuel-economy benefits to our customers,” according to Steve Gilligan, Navistar vice president of product marketing.