It absolutely was 1st released in 1939 for cars. It includes the fluid coupling and a few planetary gears. They collectively make three forward and just one reverse velocity. There is absolutely no clutch for engagement and disengagement with the motor. Bevel gearboxes have spiral and straight tooth styles. https://gearbox10741.eedblog.com/33896290/gearbox-can-be-fun-for-anyone