"D" or "2" Range First Gear

Operating Clutches, Brakes and Solenoid Valves
- Forward clutch
- Coast clutch
- One-way clutch No.1
- Solenoid Valve No.1

The engine power from the input shaft is transmitted to the rear planetary ring gear through function of the coast clutch and one-way clutch No. 0. In other words, the rear planetary ring gear turns clockwise at the same speed as the input shaft owing to operation of the forward clutch, coast clutch and one-way clutch No. 0.

The rear planetary ring gear, as it turns, causes the rear planetary pinion to rotate on its own axis clockwise while turning around the rear planetary sun gear clockwise and the rear planetary sun gear to turn counterclockwise.

On the other hand, with the front planetary ring gear prevented from turning counterclockwise by function of the one-way clutch No.1, the front planetary sun gear which is incorporated with the rear planetary sun gear rotates on its axis at such speed of the specified ratio to that of the front planetary pinions which are linked with the rear planetary pinion through the planetary carrier and turning around at the same speed. In other words, the ratio of the revolution speed between the sun gears and planetary carrier is determined by the front planetary gears set.

Previously described revolution of the rear planetary ring gear is transmitted to the rear planetary pinions (rear planetary carrier) and the rear sun gear at this speed ratio. As the planetary carrier is incorporated with the counter drive gear, the counter drive gear also turns clockwise.

When attempting to use the engine brake (when the counter drive gear tries to turn faster), the one-way clutch No. 1 operates to cause the front planetary ring gear to turn clockwise. Then, revolution of the planetary carrier is released and the engine brake does not work.