It was 1st released in 1939 for vehicles. It consists of the fluid coupling and 3 planetary gears. They collectively make a few forward and one particular reverse speed. There is not any clutch for engagement and disengagement in the motor. Bevel gearboxes have spiral and straight tooth styles. https://dantenftfq.blogmazing.com/32952562/indicators-on-gearbox-you-should-know