This spring washer sits between the axle housing and the retaining nut on the front axle of the host tractor. It applies a preload that maintains clamping force on the bearing assembly, compensating for thermal expansion and vibration during operation. A flattened or fatigued washer reduces axial preload, which can lead to bearing clearance changes and eventual axle-end play. The manufacturer machines the washer to match the original spring rate, so the clamping force remains within the design tolerance of the assembly. On reinstallation, ensure the washer is seated flat against the housing face.