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The 6 main types of car transmission explained (part one)

J&H Automotive

The word “transmission” or “gearbox” is one of those terms that many are familiar with but most people are unfamiliar with the differences between the many types of transmission in use today. The transmission is one of the vital components of any vehicle with an internal combustion engine. This guide will explain some of the most popular types of car transmission used today and how they work.

What is the transmission?

The transmission is a device designed to change the speed of the engine based on the amount of power needed. The transmission helps to transmit the power from the engine to the wheels in an optimal way.

Try to imagine a car without a transmission. With each crankshaft revolution, the driving wheels would turn the same number of times. Such a vehicle would be uncontrollable since it would always turn the driving wheels; stopping would mean turning off the engine, and starting would mean that the car would suddenly jump as soon as you turned the key. Its performance would be poor and it would use a lot of fuel. Having a transmission ensures that your car’s engine revs are optimally used, performance is improved, and you can put it in neutral. The neutral gear uses a clutch mechanism that disconnects the engine revs from the driving wheels. Transmission is simply an irreplaceable component of any car.

Throughout history, automotive engineers designed and introduced numerous types of transmissions. We can divide them into two distinctive groups: automatic and manual. Automatic transmissions have evolved a lot more than manual transmissions, especially in the last few decades. This guide will explain what you should know about car transmissions and how to spot the difference between the different types.

1. Manual Transmission

Manual transmission has been around since the beginning of the automotive age. In order to properly operate the vehicle, the driver is required to press the clutch pedal, disengaging the gearbox from the engine, manually choose the desired gear, and depress the clutch pedal to engage the transmission. Using the manual transmission demands a certain level of skill and coordinating your left leg (clutch), right foot (gas), and right hand (gear lever). Shifting requires coordinated movement in order to operate the car smoothly which is often quite challenging to learn.

The benefits of manual transmissions are the analog feel, high level of driver engagement, and sense of control. That is why manual transmission is still commonly seen in enthusiast vehicles and some sports cars. Although the manuals have lesser performance and slower shifting times, they are still highly regarded as the proper transmission by some driving purists. However, with technological improvements to automatic transmissions, manual transmissions are becoming less common.

2. Automatic Transmissions

Most modern cars have an automatic transmission, a technology that has been around since the 1940s. The concept of an automatic transmission is simple. The driver puts the vehicle in “D” (for drive), and the gearbox will execute shifting automatically. There is no clutch pedal, just the brake and the accelerator, which makes using a car with an automatic transmission much easier to operate.

The automatic gearbox is a much more complicated device than the manual, especially modern transmissions with complex electronics. The classic automatic transmission has a torque converter that replaces the clutch mechanism of manual transmission and it shifts gears smoothly without the driver’s input. The benefits of automatic are a more relaxed driving experience, efficiency, and practicality.

The automatic gearboxes started as 2 or 3-speed units, while modern automatic transmissions have 8-speed or even 10-speed boxes. The more gears the transmission has, the better it can use the engine power for high efficiency and performance. Modern advances have improved the shifting times in automatics and made them much quicker than the manuals could ever be. That is one reason automatic transmission is dominating the industry right now, and it is irreplaceable for some types of vehicles like SUVs or pickup trucks. Many modern automatic transmissions also have a “manual mode” or feature that allows the drivers to control the gearbox by choosing the desired gear themselves.

3. Continuously Variable Transmission (CVT)

The CVT is an automatic transmission since it has no clutch pedal and doesn’t require the driver to change gears. There are several types of CVT transmissions, but the most common is the pulley-based CVT which uses a V-shaped belt or chain to connect two cones, one which is powered by the engine and the other which is connected to driving wheels. When moving the cones towards and away from each other, the CVT transmission creates a different turning ratio, which results in varying numbers of the turns of the driving wheels. That is why the CVT is often called “gearless transmission.” It doesn’t have a pre-designed set of mechanical gear ratios but a continuous set of ratios used through the rev range.

The benefits of CVT transmission are the optimal use of the engine power and torque (since the gearbox is always in the right ratio), compact dimensions, and lower weight. However, the CVT transmission is rarely used in passenger vehicles since it cannot endure heavy use and towing, and it is not ideal for highway driving. The CVTs are commonly found in scooters, some machines, and the Toyota Prius.

Look for part two of this article in The Loop newspaper’s April 30, 2022 issue.

For more information on transmissions and transmission maintenance, consult the knowledgeable technicians at J&H Automotive. The shop is located at 501 W. Tehachapi Blvd., and can be reached at (661) 822-9171.