Genuine OEM Audi primary shaft, part number 05A109341. This shaft is a vital component within the engine timing assembly, designed to facilitate the precise rotation and synchronization of timing components. It is located within the timing chain drive assembly as indicated in the diagram. Genuine OEM shafts are manufactured to exact metallurgical specifications and tolerances, ensuring the durability and rotational accuracy required to maintain correct engine timing and prevent catastrophic internal engine damage.