It was initial introduced in 1939 for cars. It contains the fluid coupling and 3 planetary gears. They collectively make three ahead and 1 reverse speed. There is not any clutch for engagement and disengagement in the motor. Spur and helical gears are Employed in the sliding mesh gearbox https://gearbox81356.bloggactif.com/35055006/facts-about-gearbox-revealed