It had been 1st released in 1939 for cars. It contains the fluid coupling and 3 planetary gears. They collectively make three ahead and one particular reverse speed. There's no clutch for engagement and disengagement in the motor. Spur and helical gears are used in the sliding mesh gearbox https://gearbox31852.azzablog.com/33960197/the-ultimate-guide-to-gearbox