AP2D-36 Drive Shaft 277-3201C Compatible With DH80 Main Pump ZX70 Main Pump Excavator Pump Parts Commonly referred to as main pump drive shaft or hydraulic pump input shaft. It accepts engine drive power and rotates the cylinder block. Main Functions Transfers engine torque to facilitate high‑speed cylinder block rotation Produces hydraulic energy by driving piston shoes through repeated oil suction and discharge strokes Common Failures Spline wear and key displacement: Power