This friction disc is the driven plate in the clutch pack that transmits torque from the header drive to the cutterbar and feed components. It sits between the pressure plate and the flywheel face inside the header gearbox. When the clutch is engaged, the disc transfers rotational force; when disengaged, it stops the header drive. Wear on the friction material reduces clamping force, leading to slip under load and inconsistent header speed. The disc is manufactured to the original thickness and inner diameter so that the clutch pack maintains its designed engagement pressure without requiring shim adjustments. On reinstallation, ensure the friction surfaces are free of oil and that the pressure-plate bolts are torqued to specification.