The Power Take-Off shaft transfers rotational engine power directly to implements like rotavators, mowers, and balers. When examining a second hand tractor, engage the PTO at various engine speeds to ensure smooth operation. Check the splines for stripping, confirm the safety clutch disengages cleanly, and verify that the protective guard remains properly installed. https://blogosm.com/buying-a-used-farm-tractor-everything-you-need-to-know