What is an agitator?

A traditional top-loader has a tall finned agitator that twists back and forth to drag clothes through the water. High-efficiency machines increasingly use a low-profile impeller or wash plate instead, which is gentler and allows bulkier loads but needs different cycle settings to clean as well. Some machines now offer a removable agitator so owners can choose. Agitator dogs — small plastic ratchet inserts — wear out and cause the agitator to turn one way but not drive the load.