When my washer nears the end of the wash cycle the motor starts and stops rapily making a sound as if a silinoid is switching on and off. It does it for about 15 to 20 seconds then it stops completly, restarts, stops and then goes on to the spin. It occasionally does it when the spin starts but then goes on with the spin. It has no problem with the rinse cycle or final spin. Any opinoins??