This sealing ring fits the turbo coupling assembly in the drivetrain of the host tractor. It sits between the coupling housing and the rotating shaft, preventing oil leakage from the hydraulic circuit that engages the turbocharger drive. A worn or hardened ring causes a pressure drop in the coupling, leading to delayed turbo engagement or slippage under load. The original-manufacturer ring is molded to the same cross-section profile as the factory seal, which maintains the correct interference fit against the shaft without requiring shimming or adjustment. On reinstallation, ensure the sealing surface is clean and free of burrs, and lubricate the ring lightly before assembly.