Peterbilt Motors Co. is making Allison Transmission its exclusive supplier of automatic transmissions for its medium-duty line of trucks, as well as several heavy-duty models.

Allison’s 2000 and 3000 Series transmissions for on/off highway applications are now going to be the standard automatic selection for Peterbilt’s Model 330, Model 335, and Model 340 medium-duty trucks. The Allison 2000 Series is available with and without PTO and is rated at 340 hp. and 660 lb.-ft. of torque, while the Allison 3000 Series, also available with a PTO option, is rated at 370 hp. and 1250 lb.-ft. of torque.

On Peterbilt’s Model 365, Model 367 and Model 388 heavy-haul, construction and oilfield service trucks, the Allison 4000 Series transmission becomes standard fare – a product rated at 500-600 hp. and up to 1850 lb.-ft. of torque that can also be equipped with a PTO.

Jim Wanaselja, director of North American marketing sales and service and global business activities for Allison, noted that his company’s formal partnership with Peterbilt also includes research and development efforts, focusing on better product integration to help improve fuel economy and reduce emissions.