1997 Chrysler Town and Country Windshield front wipers quit

1997 Chrysler T&C Van windshield wiper problem: The front wipers stopped moving but the motor runs very noisy at high speed. How can this be fixed? Is it a problem outside the motor/gear assembly (like a disconnect between the gear driveshaft and the wiper arm assembly, or is it the integrated motor/gear assembly itself? How can it be fixed and how much should it cost, depending...