Ride Control

Has anyone ever had troubles with the ride control making a high pitched screeching sound (almost like the gears are grinding)? I think that it is almost shot. If so is it expesive to replace or can I just unplug it when it finally quits and not worry about it? I am worried If I do that I will probably hear that wonderful "ding ding" and the display will read service ride control! My Aurora has 170,000 miles on it, so I am not too concerned if the car has it or not.