Genuine OEM Audi Automatic Transmission Output Shaft Seal, part number 0AT409399. This critical sealing ring is installed on the automatic transmission output shaft to prevent fluid leakage, maintaining proper lubrication and pressure within the transmission. Weighing 0.036 kg and measuring 0.075 m in diameter, it provides a precise and secure fit. Using a genuine OEM seal ensures the correct material composition, flexibility, and dimensional accuracy, which are essential for long-term leak prevention and transmission reliability.