The Whirlpool WP21001108 Plastic Motor Pulley transfers rotational motion from the washer motor to the drive system to support drum movement during laundry cycles. This replacement pulley connects to the designated drive components and rotates with the motor to transmit mechanical force through the washer’s drive mechanism. Its function supports consistent power transfer and proper movement of the washer’s drive system. A cracked, worn, or damaged pulley may cause unusual noises, slipping, or problems with washer movement. Replacing a faulty pulley can restore proper drive transmission.