This clutch shaft thrust washer sits on the shaft between the clutch assembly and the flywheel or gearbox input. It absorbs axial loads generated during clutch engagement and disengagement, preventing the shaft from contacting the housing directly. A worn or collapsed washer allows end-float that can cause misalignment of the clutch disc and release bearing, leading to incomplete disengagement or chatter. The original AGCO part is machined to the same thickness as the original assembly, so the clutch stack height and release-bearing travel remain within specification. On reinstall, verify the washer is seated flat against the shoulder and that the shaft turns freely before closing the housing.