However, the torque converter’s fluid coupling between the engine and transmission transmits little or no torque at low rpm. This fluid coupling permits the car to stop without stalling the engine — an identical perform to the clutch assembly in a manual transmission driveline. Designers could choose automotive gears plastics for one profit and discover features from many others. For instance, a producer switched from a forged iron transmission to one using glass-reinforced Celcon® acetal copolymer to cut back noise in a five-gear, dual-drive washer transmission.