Overdrive One Way Clutch (OWC) Mechanical Diode
The overdrive OWC mechanical diode is a one-way clutch which also acts as the coast clutch pressure plate. It provides direct drive through the overdrive gearset when in power on mode. It overruns in power off mode or when the overdrive clutch is applied.
Engine torque is transmitted in first, third, and fifth gears while the range selector lever is in the (D) position. The input shaft drives the overdrive carrier clockwise. The overdrive carrier has the coast clutch hub bolted to it which also turns clockwise. The overdrive sun gear would turn counterclockwise, but is held from turning by the coast clutch mechanical diode. The input shaft turns the same speed as the center shaft and transmits torque through it.
In second, fourth and sixth gear the overdrive clutch is applied, the mechanical diode overruns and holds the overdrive sun gear fixed to the case. This causes the overdrive planet to walk around the sun gear and over-drive the overdrive ring gear.
Mechanical diodes are model dependent. The higher rpm of the gasoline engines require a mechanical diode unique from that used on higher torque diesel engines.