This turbocharger coupling seal sits between the turbocharger output and the drivetrain coupling assembly. It prevents oil leakage and maintains pressure within the coupling housing during torque transmission. A worn or hardened seal allows oil to escape, which reduces coupling engagement force and can lead to slippage or drivetrain noise. Manufactured by AGCO, the seal is molded to the same cross-section profile as the original coupling housing groove, ensuring proper compression without over-tightening the retaining hardware. On reinstallation, clean the groove surface and verify the seal is seated evenly before closing the housing.