Abstract: An auxiliary power system is provided for a vehicle having a frame with two longitudinal beams, in which the system includes an auxiliary power unit (APU) mounted on a support frame that is pivotably mounted to the vehicle frame to permit pivoting in a vertical plane. The support frame further includes The support frame further includes a suspension system at an intermediate location between the pivot mount and the APU to help isolate the APU from the effects of road vibration. The APU itself is mounted on rollers so that the APU can be slid out of its housing for access and/or removal. The housing door is configured to provide a rolling surface onto which the APU can be moved when the door is open. The APU includes an engine exhaust heat exchanger that scavenges engine heat to heat the vehicle. A rotating cleaning auger is mounted within the heat exchanger to clean the surfaces of debris left by the engine exhaust gases.