Types of Automatic Transmission

Most Indians drive manual transmission cars. For many years automatic transmission has remained a luxury as it was mostly available with higher end cars. The total consumption of automatic cars is only 6-8% in India.  The cars with different types of automatic transmission are slowly gaining popularity. People are gradually realizing the advantages of gear free, clutch free and stress-free driving with automatic cars. Maruti sold 900 units in 2013-14, is currently selling 94,000 units annually and aim to sell 3 lakh units by 2020. You can read more about automatic vs manual – Automatic is easy and will change your life.

Automatics can be relatively expensive but are more comfortable to drive. Every manufacturer is offering different types of automatic transmission. It can be confusing sometimes to choose which is the right automatic transmission for you. This blog explains the different types of automatic transmission, its pros, and cons.

AUTOMATIC (AT) or FULLY AUTOMATIC

Automatic also known as the torque converter is a fully automatic transmission which changes gear automatically as you start driving and there is no involvement of driver to press clutch or change gear. It uses a torque converter to transfer power from the engine to the transmission. It is hydraulically operated using a fluid coupling or torque converter, and a set of planetary gearsets to provide a range of gear ratios.

Conventional automatics are very smooth in operation whether taking off or changing gears but usually lack best fuel economy because of the slight slip of the fluid-filled torque converter and driving the hydraulic pump that operates the clutch packs.

Pros: a smooth shifting of gears, no loss of energy; Cons: less mileage, expensive

Example: Hyundai i10, Creta, Skoda Rapid, Toyota Innova Crysta

AUTOMATED MANUAL TRANSMISSION (AMT)

AMT is also known as semi-automated transmission (SAT) and is not an automatic transmission in the real sense but works just like an automatic transmission. This automatic transmission type utilizes a regular clutch and gear setup (which is not visible) but automates the action by the use of sensors, actuators, processors, and pneumatics. AMT is a kit which can be installed with any manual car and has helped manufacturers introduce low-cost automatic cars. These are very simple, affordable, fuel efficient and not very expensive to repair.

AMT is based on an electronic control unit and a hydraulic system that supervise the use of the clutch and the gear shifting, allowing the driver to change gear without using the clutch, either sequentially or fully automatically.

Pros: good mileage, not expensive, cheaper to maintain; Cons: drop in driving force or acceleration during the gear shifting, shift-shocks or jolt-filled experience

Example: Maruti AltoK10, Celerio, Dzire, Renault Kwid, Tata Tiago, Toyota Corolla Altis, Yaris

CONTINUOUSLY VARIABLE TRANSMISSION (CVT)

CVTs do not come with a set of gears like other automatic transmissions but use a belt that runs between two variable-diameter pulleys to give a wide range of ratios and a smooth transition between them. CVTs can smoothly and effortlessly alter its gear ratio by varying the diameter of a pair of belt or chain-linked pulleys, wheels or cones.

The real advantage of a CVT is that the engine can be kept at its most efficient speed while the transmission adjusts to changes in load or road speed. Whether you accelerate to high speeds, cruise or slow down, the transmission constantly makes adjustments to road speeds while the engine is kept at a consistent rpm for best fuel economy.

Pros: Very smooth shifting and step-less driving experience, no loss of power, very good fuel economy; Cons: rubber band effect, can be noisy, cannot handle high torque for performance cars

Example: Maruti Baleno, Honda City, Jazz, Nissan Micra

DUAL CLUTCH TRANSMISSION (DCT)

A dual Clutch transmission as the name suggests uses two separate clutches for gear changing – one for odd-numbered and another for even-numbered gears. Both the shafts have their own clutch. It can fundamentally be described as two separate manual transmissions with their respective clutches contained within one housing and working as one unit. This gearbox changes gear faster than a human can, making it the fastest gearbox available on the market. They are usually operated in a fully automatic mode, and many also have the ability to allow the driver to manually shift gears in semi-automatic mode.

Pros: Fastest gear shifting, superb acceleration, better fuel economy, ideal for high-performance vehicles Cons: initial pick up is slow, costly

Example: Ford Figo, Aspire, EcoSport

DIRECT SHIFT GEARBOX (DSG)

Its very similar to DCT as it uses two clutches instead of a torque converter, and its mechanism works by simple disengaging of one clutch and engaging the second one for changing the gears. This transmission offers faster gear shifting and smoother pulling away than the traditional models. The latest DGS transmissions provide better mileage than the manual transmissions.

Pros: better mileage, smooth changing of gears, no jerks; Cons: Long-term reliability concerns, a bit sluggish on downshifts

Example: Skoda Superb, Volkswagen Polo GTI, Vento, Ameo

So if you are exploring an automatic car it might be best to understand the types of automatic transmission available in the market and which might be relevant to your driving style, budget, and needs. Wishing you all the best!

You can also read my other blog related to Automatic cars here – Automatic is easy and will change your life.

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