You must have had this question in mind when you buy a car, which transmission should I choose Should it be a manual Should it be an automatic What difference does an automatic make over a manual
Before understanding more about different types of transmissions, let us understand what a transmission is. A transmission consists of gearbox, clutch, propeller shaft and final drive. The basic purpose of a transmission is to adapt the output from an engine to the final drive wheels by using different ratios of gears. You can either choose to operate them manually or let an automatic system take care of it.
There are various types of transmissions available in the market. The types of transmissions that most of the manufacturers use are
- Manual Transmission (MT)
- Torque Converter Automatic (AT)
- Dual-Clutch Automatic (DCT or DSG)
- Automated Manual Transmission (AMT)
- Continuously Variable Transmission (CVT)
Manual Transmission (MT)
A manual transmission consists of 5 or 6 gears of different ratios, a clutch and a gear lever. In this, the driver gets to choose the gear in which he likes to drive. A major chunk of car manufacturers uses this type of transmission in their vehicles, as this transmission is relatively cheap to produce and is more efficient.
Having a manual transmission gives the driver the ability to choose his own gear while driving. This also helps in better economy of the vehicle, whereas the downside of this transmission is the extensive wear and tear of clutch. You have to slot in the gears perfectly and release the clutch appropriately. Also, operating a manual transmission car when you are stuck in traffic is cumbersome, as you have to change gears extensively.
Most of the car enthusiasts prefer this kind of transmission, as driving a manual car gives a completely different driving feel altogether. Having a manual transmission car helps in driving better as you get to know when to shift, when to engage clutch and understand your car better, and make you a better driver.
Torque Converter Automatic Transmission (AT)
An automatic transmissions basic function is the same, sending engine output to the wheels. But it is done with the help of a torque converter. The transmission contains different sets of gears, but in order to select the appropriate gear, the car does it for you with the help of an electronically controlled hydraulic operated clutch.
When this technology was first introduced, they were not as efficient as the conventional manuals, but over time they have grown to become efficient. The best advantage of this transmission is it completely eliminated the need of having a clutch pedal at all.
The best part of having a torque converter is ease of driving. You can drive at slow speeds with ease. You need not worry about your clutch and the gear you are in, as the computer takes care of it all. The main disadvantage is fuel efficiency. As there is a slight slip in the fluid filled torque converter, your fuel efficiency takes a toll.
Most of the luxury car manufacturers who sell their cars in India have this type of transmission equipped in their vehicles
Automated Manual Transmission (AMT)
An Automated Manual Transmission or more commonly known as AMT/Flappy Paddle Gearbox/SMT is a type of transmission that is similar to a manual transmission, except that the clutch is electronically controlled by a lever that is connected to a module.
In this, the gear operation is either done automatically or by the help of a sequential shifter or paddle shifter. This transmission is as efficient as conventional manuals, in fact sometimes an AMT is more efficient than the manual.
Most of the low-cost manufacturers like Maruti and Hyundai use this type of transmission. Some exceptions include supercars such as the Lamborghini Aventador, erstwhile BMW M5 etc.
In motorsports, this type of transmission is still used.
Dual-Clutch Transmission (DCT)
A Dual Clutch Transmission, or more commonly known as DCT is completely different from the conventional automatics available in the market. This transmission uses two clutches rather than a single clutch. This transmission can be described fundamentally as two separate manual transmissions working simultaneously
How this transmission works is there are two clutches in the gearbox. One clutch operates the even gears and another one operates the odd gears. This transmission achieves lightning fast shifts without disturbing the torque spread, thereby making it more suited towards road cars.
The main advantage of having a Dual Clutch Transmission is shorter shift times, which helps in smoother acceleration while reducing lag during shifts. Disadvantages include high manufacturing costs and maintenance of gearbox.
This type of transmission is popular among the Volkswagen Group cars, that include Skoda, Audi, Lamborghini, Buggati, Bentley, Porsche (PDK), Seat etc..
In motorsports, this gearbox is widely used. For example, the current generation F1 cars use a sophisticated Dual Clutch Transmission system to reduce shift times.
Continuously Variable Transmission (CVT)
Continuously Variable Transmission, or commonly known as CVT, is different from manual or automatics. In this there is no clutch of any sort, but has a belt driven system for driving the wheels. This type of gearbox is mostly found in cars made by Nissan, Datsun, Renault etc.