This PTO O-ring seals the connection between the tractor's power take-off shaft and the driven implement, preventing hydraulic oil or gearbox lubricant from leaking at the coupling point. It sits in the groove on the PTO housing or shaft, compressing against the mating face when the implement is attached. A worn or hardened O-ring allows fluid to weep past the seal, which can lead to a gradual loss of lubricant and eventual bearing damage in the PTO driveline. As an original component, it is molded to the same cross-section and durometer as the factory seal, ensuring it seats correctly in the groove without requiring additional shims or adapters. Replace the O-ring whenever the PTO shaft is removed or the implement coupling is serviced.