An automobile requires high torque when climbing hills and when starting, even though they are performed at low speeds. On other hands, when running at high speeds on level roads, high torque is not required because of momentum.

So the requirement of a device is occur, which can change the vehicle’s torque and its speed according to road condition or when the driver need. This device is known as transmission box.

gear box

The gear box is the second element of the power train in an automobile. It is used to change the speed and torque of vehicle according to variety of road and load condition. A gear box changes the engine speed into torque when climbing hills and when the vehicle required. Sometimes it is known as torque converter. Main functions of a gear box is as follow-

Also Read: Differential Gear & Its Working

  1. Provide the torque needed to move the vehicle under a variety of road and load conditions. It does this by changing the gear ratio between the engine crankshaft and vehicle drive wheels.
  2. Be shifted into reverse so the vehicle can move backward.
  3. Be shifted into neutral for starting the engine.

Main components of a gear box:

1. Counter shaft:

2. Main shaft:

3. Gears:

4. Bearings:

Working of a principle gear box: