This o-ring seals the connection between the turbocharger and the coupling housing in the drivetrain. It prevents pressurized oil from leaking at the joint, maintaining the hydraulic pressure needed for the turbo coupling to transmit engine torque to the transmission input. A failed seal causes a pressure drop, resulting in clutch slip and a loss of power delivery under load. As an original AGCO part, the o-ring is molded to the specified cross-section and durometer, matching the seal groove geometry of the housing so no adapter or shim is required. Install a new o-ring whenever the coupling is disassembled; lubricate the seal before assembly to prevent rolling or pinching.