Not sure what you mean by a rattle. Do you mean a "klacking" sound? That would be the motor coupling. Easy enough to change-out. Pull the body cover by removing the two screws that hold the control panel to the body, roll the control panel up, and remove the two clips on either side of the body to the rear panel using a flat head screw driver. Tilt the body back toward you, and remove. Take the clips off the pump motor, and then the clips on the motor. The coupling is a three-prong piece of plastic with a rubber cushion between it and the other coupling on the transmission. Break the old coupling, and replace with a new set, that has a metal keen-sert where it must be hammer-tapped onto the shaft of the transmission and the motor shaft. Be careful to use a 7/16" socket to tap the couplings on, or you will break them around the base on the transmission and motor posts. Realign the couplings through the rubber buffer, and re-clip the motor and the drain pump. Reassemble the body by holding the body by the top lid, tilt 30 degrees toward you at the lid, and slide the bottom of the body under the bar near the floor. Be careful to push the fill spout under the top of the body before replacing the clips, and the screws to the control panel.