This cap seals the rear axle housing at the drive system interface, preventing lubricant loss and keeping contaminants out of the final-drive gear set. It mounts at the outer end of the axle tube, directly behind the hub assembly. A missing or damaged cap allows dirt ingress that can score bearing surfaces and accelerate gear wear. As an original AGCO component, its sealing face matches the housing bore profile to maintain the specified interference fit without additional sealant.