This pulley drives the chaff distributor rotor in the cleaning assembly of a combine harvester. It transmits belt-driven power from the cleaning fan or drive shaft to the rotor that spreads chaff across the width of the sieves. A worn or damaged pulley causes belt slippage, which reduces rotor speed and leads to uneven chaff distribution across the cleaning shoe. The pulley is machined to match the original bore and keyway dimensions, so it mounts directly onto the rotor shaft without requiring adapter bushings. When replacing, inspect the belt for wear and verify the pulley runs true to avoid vibration in the distributor assembly.