This friction disc transmits torque from the engine to the PTO driveline when the clutch is engaged. It sits between the pressure plate and the flywheel in the PTO clutch pack, and its friction surfaces provide the grip needed to drive the implement shaft. Wear on the disc reduces clamping force, which leads to slip under load and inconsistent PTO speed. The manufacturer machines this disc to the same thickness and surface finish as the original assembly, so the clutch pack maintains its designed engagement pressure without requiring shims or adjustments. On reinstall, ensure the disc is centered and the pressure plate bolts are torqued to specification.