This O-ring seals the connection between the power take-off (PTO) shaft and the housing, preventing oil leakage from the transmission or engine. It sits in the groove at the PTO output flange, where it compresses against the mating face to maintain a closed hydraulic circuit. A degraded or hardened O-ring allows fluid to weep past the seal, which can lead to a drop in PTO clutch engagement pressure and eventual clutch slip. As an original AGCO component, the O-ring is molded to the same cross-section and durometer as the seal originally installed in the housing, so it seats without distortion and maintains the correct squeeze against the groove walls. On reinstallation, ensure the groove is clean and free of old sealant before fitting the new ring.