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 450 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.