To the layman, there are two types of transmissions: automatic transmissions and manual transmissions. The difference? One changes gears automatically, while you need to manually shift gears with a clutch in the other. And that’s perfectly fine; if your car is just a tool to get you from point A to point B, any automatic transmission can serve as a massive quality-of-life upgrade. However, for those looking beyond the term “automatic,” while making their purchase decision, it can get very confusing quickly, thanks to the abundance of technologies marketed as automatic transmissions.
What Is A Transmission?
A transmission matches the speed of the engine with the speed of the wheels, in simple language. Your engine can only spin in a certain range. This range varies for each engine, but never exceeds about 10,000 RPM and is always above 800 RPM. However, the wheels rotate at wildly different speeds from the engine; while the engine spins above 1200 RPM in operation, at a relaxed speed of about 40 km/h, the wheels rotate at just 400 RPM. At this speed, any engine would stall. A solution was needed to effectively transmit engine power to the wheels while accounting for a range of speeds the vehicle would be driven at; hence, the transmission was born. It involves gears with varying ratios designed to be an intermediary between the wheels and the engine & is responsible for matching their speed. An automatic transmission is one where a computer shifts gears for the driver, and a manual transmission involves the driver shifting gears with their input. They essentially perform the same task.
Should I Buy A Manual Or An Automatic?
The decision between an automatic transmission and a manual transmission is subjective; purists prefer a manual transmission as it gives them more control over the vehicle. However, automatic transmissions serve as a boon in bumper-to-bumper traffic and make driving easier and accessible to a larger group of people. People usually prefer automatic transmissions in more premium cars.
What Type Of Automatic Do I Choose?
After choosing between an automatic transmission & a manual transmission, it’s easy to get confused amidst the sea of options in the market today. Let’s try to find order amidst the chaos:
- Torque Converter Automatic (TC)
- Operation: Engine torque is transmitted hydraulically and not mechanically – this eliminates the need for a clutch. Planetary gearsets enable multiple gear ratios, controlled by hydraulic pressure and electronic solenoids. Modern versions such as the ZF8 use lock-up clutches and up to 10 speeds for efficiency.
- Advantages: High torque tolerance, smooth power delivery & reliability.
- Disadvantages: Heavy & lower fuel efficiency than a conventional manual transmission.
- Cars Powered: This type of transmission powers most automatic diesel vehicles. It also powers Volkswagen & Skoda’s 1.0L TSI engines in vehicles like the Kylaq.
- Dual-Clutch Transmission (DCT)
- Operation: The next gear is pre-selected by a secondary clutch. The gearbox analyses the driver’s behaviour and guesses what gear they might need next. Also called PDK/DSG.
- Advantages: Lightning-fast gear shifts, high fuel efficiency & enthusiast-class performance.
- Disadvantages: Complexity, potential overheating in low-speed traffic, higher cost.
- Cars Powered: Dual-clutch transmissions power performance-oriented vehicles such as the Hyundai Verna 1.5L Turbo, Hyundai Creta N Line, Volkswagen Virtus GT & Skoda Kodiaq.
- Continuously Variable Transmission (CVT)
- Operation: This transmission adjusts its ratios continuously to maintain ideal engine RPM throughout.
- Advantages: Best fuel economy & the smoothest drive experience.
- Disadvantages: “Rubber-band” effect resulting in delayed acceleration, not as fun to drive as the others.
- Cars Powered: All automatic Honda vehicles, non-turbo Hyundai Verna, Creta & Kia Seltos variants.
- Automated Manual Transmission (AMT)
- Operation: This is a manual gearbox with electronically controlled clutches that change gear automatically.
- Advantages: Tend to be cost-effective, lightweight & fuel efficient.
- Disadvantages: These aren’t as refined as the others & aren’t considered to be a true automatic transmission. Gear shifts can be jerky.
- Cars Powered: Economy cars like the Maruti Alto, Maruti Baleno & Maruti Dzire.
- Clutchless Manual Transmission
- Operation: This is a traditional manual gearbox that’s been modified to eliminate the need for a clutch pedal. The clutch is electronically controlled, but the gear shifter is not. Unlike an AMT, the transmission doesn’t change gears automatically; the driver must shift.
- Advantages: They simplify driving for those who find clutch operation challenging, while still being fuel efficient, cost-effective & lightweight.
- Disadvantages: Lack of refinement, poor shift quality, jerky acceleration.
- Cars Powered: Kia Carens, Kia Sonet, Hyundai Venue
In summary, there are three types of proper automatic transmissions; CVT, TC & DCT. Other options such as AMTs and iMTs offer some convenience over manual transmissions, yet they aren’t comparable to full-fledged automatic transmissions. Choose a dual-clutch transmission if you’re an enthusiast and want instant gear shifts, a CVT if you’re a sedate driver who values a smooth driving experience, or a torque converter if you value reliability & robustness.
