2021 Peterbilt 579, Cummins, X15, 400HP, Fuller 12 Speed Transmission, Sleeper, , , Stock # 1151048 2021 Peterbilt 579 80-inch Ultraloft Double Bunk Sleeper for Sale. Cummins X15 Engine with 500 Horsepower. ThermoKing APU Unit. Bumper Guard, Solar Powered Power Inverter. 12-speed Automated Endurant Eaton Transmission. Fresh PM Service & DOT Inspection- $59,977 Price does not include state and local taxes; tags; registration or title fees; dealer-imposed fees, including document preparation, processing or servicing fees, or any optional equipment or upfitting work selected by buyer. Valid while supplies last. Images shown may not reflect actual vehicle.