A quick observation of the interior of a car will indicate whether the car has automatic or manual transmission system. There exist two notable differences between the two transmissions; a car with automatic gearbox transmission lacks the clutch pedal and the gearshift. Exciting, right? Then how does the car operate? It means that after you set the transmission to "Drive," all other operations will be automatic. Does this sound like a cool ride? Read on to find out what an automatic gearbox is and how it operates;

Automatic Transmission

Transmission is the medium that aids in the conversion of engine force into one reliable source of power that puts the car into motion. The high power produced by the engine is quickly transmitted to the wheels as torque, a huge rotational force. The force rotates the wheels causing the car to move. The speed at which the engine rotates is not proportional to the rate at which the wheels are expected to turn: while the engine makes rotations of as high as 500 to 7000 rotations per minute, the wheels rotates at between 600 and 1800 rotations per minute. The two rotations need to be harmonized to protect the driver from reaching extremely high speeds or having difficulties in stopping. Transmission aids in sending only enough power to the wheels to cause the desired movement using gear ratios.

What is Gear Ratio?

Automatic transmission changes the gears automatically as opposed to the manual system that requires regular changing of the gear by the driver. But what is gear ratio? The transmission uses many gears that have fit in markings on their surface; as a result, one gear affects the rotation of the other gear. The different gears have different numbers of teeth. This means that for gear with 20 teeth to be rotated once by another one with ten teeth, the gear with ten teeth must make two rotations. The gear ratio is calculated by dividing the number of teeth on the output gear with that in the input gear. In this case, the ratio is 10:20 which can further be simplified to 0.5:1. The number of gear interactions can be increased beyond two gears. The rotations of the gear will determine the gear ratio and consequently the speed of the vehicle. Depending on the environment, the automatic gear systems will switch without driver's intervention to increase the torque.
The number of rotations made affects the torque and consequently the speed of rotation of the car. In the automatic transmission, the changing of the gears is automated at through fluid pressure. The fluid activates the clutch and determines which gear the vehicle should use the planetary gear set; a sun gear surrounded by planet gears and enclosed in a ring gear, then switch to that gear automatically.

Key Points to Note about Automatic Gear Box

The automatic gearbox does not require manual changing of the gears by the driver. The gear box is made of many gears with a different number of teeth that interacts to produce gear ratio. The gear ratio in application determines the strength and the speed the car uses. In the place of the clutch, automatic engines have torque converters. The impeller is connected to the engine; it is rotated by the engine and send high-pressure liquid which turns the turbine. The rotations produce torque which is transmitted to allow the rotations of the wheels.

Advantages of automatic transmission

When compared to the manual system, automatic gear system has several advantages including; the ease in driving due to automatic gear change and the absence of a clutch. The two features allow the driver more time since they don't have to do so much at an ago to move the car. Additionally, an automatic transmission is easy for new learners to apply due to the less energy required.


The automatic gearbox is a complicated system that works in a well to eliminate the need for manual gear as well as the clutch. It is a sophisticated system that applies gear ratios and torque force to move the car.