AMT, CVT, DCT or torque converter: which automatic should you buy?

AMT: a manual with a robot clutch

An automated manual transmission is an ordinary manual gearbox with an electric actuator that presses the clutch and changes gear for you. It is light, simple and cheap to make, so it is the most affordable way to drop the clutch pedal, and its mileage is close to the manual's.

The catch is the shift itself. Like a person changing gear, the AMT has to cut power, press the clutch and select the next gear, so there is a pause and a slight nod on each upshift, most noticeable when you accelerate hard. You learn to lift off the accelerator a little as it changes and it becomes smooth. On a steep slope from a standstill, choose a car with hill-hold assist.

You find AMTs in the Tata Tiago, Punch and Nexon, Maruti's AGS cars and the Nissan Magnite, usually for about ₹55,000 to ₹70,000 over the manual.

CVT: no gears at all

A continuously variable transmission uses a belt between two pulleys that change size, so it has no fixed gears and never 'shifts'. In stop-and-go traffic it is the smoothest of the four, with no jerks at all, and it keeps the engine at its most efficient speed.

Push hard, as when overtaking on a highway, and the engine revs rise and stay high while speed catches up, the so-called rubber-band feel. Most modern CVTs imitate steps when you accelerate hard to reduce this. Driven calmly, they are relaxing.

Honda's City and Amaze, the Nissan Magnite and Hyundai's 'IVT' cars such as the Creta use them. On the City the CVT is about ₹1 lakh over the manual, and on the Creta petrol about ₹1.35 to 1.45 lakh.

DCT: two clutches, very quick shifts

A dual-clutch transmission is two gearboxes in one: one clutch holds the odd gears, the other the even ones, and the next gear is already lined up before it is needed. Shifts are almost instant and there is no loss of pull, which makes turbo-petrol cars feel lively. Efficiency is close to the manual.

At a crawl, a DCT has to slip its clutch like a learner driver, so some can feel hesitant or slightly jerky when inching forward in a jam, and long stretches of creeping can heat the clutch. Modern ones handle Indian traffic far better than early units did.

Hyundai and Kia's 7-speed DCTs, Tata's DCA in the Nexon and Curvv, and Volkswagen and Skoda's DSG are all dual-clutch. The Kia Sonet's DCT is about ₹66,000 to ₹80,000 over the manual, and the Nexon Creative petrol DCT ₹1.25 lakh.

Torque converter: the traditional automatic

The classic automatic connects the engine through a fluid coupling instead of a clutch plate, then uses planetary gears to change ratios. It creeps smoothly in traffic, shifts gently, copes with heavy loads and steep hills, and is very durable, which is why it is common on diesels, SUVs and off-roaders.

It loses a little more energy than the other three, so mileage is usually slightly lower, although modern six- and eight-speed units have closed most of the gap. It is often the most expensive option.

The Maruti Brezza, Skoda Kylaq, Mahindra XUV700 and the Creta and Sonet diesels use one. It is ₹1.3 lakh over the manual on the Brezza, ₹1 lakh on the Kylaq and about ₹70,000 to ₹1.1 lakh on the Sonet diesel.

The four side by side

How they compare on the things that matter day to day:

Which one suits you

• Mostly city driving on a tight budget: an AMT. Learn to ease off as it shifts and it is perfectly livable.
• Long daily commutes in heavy traffic: a CVT or a torque converter. Smoothness matters more than speed when you crawl for an hour.
• You enjoy driving and your roads move: a DCT, ideally with a turbo petrol.
• Hills, a full car often, or a diesel or 4x4: a torque converter.
• Whatever you choose, test-drive that exact gearbox in traffic and on a slope before you sign.