Automatic gearboxes explained: what are the different types of automatic car?

There are only so many hours you can sit in a queue of traffic, left leg pumping at the clutch every few seconds as traffic crawls forwards, before you realise the value of an automatic gearbox.

Automatics have been a feature in cars for over a century, and became particularly popular in the automotive boom in the United States following the Second World War, but today they’re a common feature in cars in almost every market around the world.

Over the years automatic gearboxes have not just become even smoother than they used to be, but also offer a more direct driving feel. What’s more, it’s no longer unusual for an automatic car to offer better official fuel economy figures than its manual equivalent, thanks to optimised gear ratios and shift points.

History of automatic gearboxes

The first automatic car gearboxes appeared in the early 20th century, just a few decades after the invention of the car itself, but it was General Motors that arguably both perfected and popularised the auto with its “Hydramatic” – introduced in 1939. This is considered the first mass-produced automatic transmission for passenger vehicles.

At this time, most manual gearboxes didn’t even have synchroniser rings, requiring drivers to double-declutch both up and down the gearbox to make (somewhat) smooth changes, so the benefit of a gearbox that did everything for you was clear. After the Second World War, and in the USA especially, the rapid increase in consumer purchasing power and the huge private car market that followed led to greater traffic on the road, and automatics quickly became de rigueur in the American cars of the late 40s and the 1950s.

Throughout the latter half of the 20th century automatics were widely adopted in larger luxury cars but tended to be an expensive option on smaller cars, but CVT (continuously variable transmission) gearboxes became popular in smaller cars such as the Nissan Micra and Rover Metro in the early 1990s, and automated manuals took off in the early 2000s, having jumped from sports cars like the Ferrari F355 to city cars like the Smart Fortwo and Fiat Seicento. 

Pros and cons of automatic gearboxes 

Ease of use is the biggest benefit of automatics: simply press your foot on the brake to disengage a shift lock (preventing the car starting off by mistake), shift into Drive, and you’re good to go. There are only two pedals to operate, effectively making operating a car a case of “go” and “stop”.

Over time, improvements in technology have also reduced some of the auto gearbox’s weak areas. Modern automatics are more fuel-efficient, both because they can choose better gearshift points than most drivers, and because they lose less power through their hydraulics than they used to. Shift speeds have also improved, both through technologies like dual-clutch automatics, and refinements made to older ones. There’s even a fun factor for some drivers – the appeal of flipping paddles like an F1 driver is just as high today as it was when Ferrari touted the benefits with its “F1” gearshift in the mid-nineties. Plus, you get to keep your hands on the wheel even in the trickiest driving conditions.

Downsides of automatic gearboxes include their weight and mechanical complexity. A manual tends to be a lot simpler and lighter, and in the event that a component of the transmission needs repairing or replacing, generally cheaper too. Talking of cheap, while low buyer demand has made manuals the more expensive option in some sports cars, autos do tend to still cost extra in cars where they aren’t specified as standard, which can raise the price of smaller, cheaper cars in particular.

Then there’s the driver appeal factor. It’s probably fair to say the majority of modern drivers prefer the ease of driving an automatic, but if you take pleasure from the interactivity of shifting gears yourself, balancing throttle, clutch, and gearshift just-so, and the direct and intuitive feeling of knowing how a car will behave in a given gear at a given engine speed and throttle load, then an auto just won’t cut it. There’s a reason Porsche’s RS division suggests its PDK automatics are cars for the track, but it releases special models like the 911 S/T, with a manual gearbox, purely for fun.

What are the different types of automatic gearbox?

As a car buyer you’ll be confronted by various different technologies under the automatic gearbox banner. Let’s look at the most common systems and explain in simple terms what they are…

Torque converter automatic gearboxes

The most common kind of automatic transmission is often referred to as a torque converter, though the torque converter is technically the fluid coupling that progressively transfers engine power to the gearbox, rather than being the gearbox itself. Traditional automatics use hydraulics and planetary gears to select certain ratios.

In modern times, the number of ratios in torque converter automatics has increased – some gearboxes have up to 10 speeds now – while shift times have got faster, and torque converters “lock up” sooner, for a more direct feel than older gearboxes that earned the nickname “slushboxes” as a result of their vague and slow responses. Traditional autos tend to offer a very smooth, easy driving feel, and the best make gearshifts almost imperceptible – the eight-speed gearbox from German firm ZF, used by multiple manufacturers, is nearly as quick as a system dual-clutch in some applications, but also very smooth in operation.

Read more in our guide to torque converter autos…

Dual-clutch transmission gearboxes

Dual-clutch transmissions or DCTs have become the go-to automatic for certain manufacturers (such as the Volkswagen Group which refers to the tech as DSG - Direct Shift Gearbox) and certain types of car (such as high-performance hot hatches, or supercars). Introduced in the 1960s and used in racing in the 1980s, their modern use was introduced by Volkswagen on the Golf R32, and they took off in popularity soon after.

Inside the transmission, odd-numbered gears and even-numbered gears are engaged by different clutches, and the gearbox can swap almost instantly between them, for smooth, fast shifts and a direct driving feel like a manual gearbox, making them popular on performance cars. Ferrari and Porsche’s DCTs are among the best, with lightning-fast shifts and tactile paddles on the steering wheel to enact them.

Read more in our guide to dual-clutch gearboxes…

Single-clutch automated manual gearboxes

Before dual-clutch gearboxes became common, single-clutch automated manuals were popular in everything from city cars to supercars. In fact, it was the likes of Ferrari that popularised them, the brand’s “F1” shift at least partly replicating the feel of Ferrari’s F1 cars, with paddles to change between ratios.

Often based on conventional manual gearboxes, but with automated operation, they’re lighter and mechanically simpler than torque converter autos or dual-clutch autos, but they can be a little jerky in operation, too. The best can be fast and exciting in a supercar, often changing the fastest under full throttle, but the worst give you lurching pauses between every gear change, and unpredictable low-speed manoeuvring – not ideal given their brief popularity in city cars.

Clutchless manual transmission gearboxes

There aren’t a lot of clutchless manual gearboxes around any more, but for a while this was the best combination of manual and automatic that carmakers could come up with. Offered by the likes of Saab (as Sensonic) and Renault (as Easy), the driver still moved a regular manual gear lever around an “H-pattern” gate, but there was no clutch pedal to operate.

Instead, the clutch would electronically engage as you pressed on the accelerator to pull away, and disengage as you touched the gear lever to move it to the next gear, before re-engaging again as you applied the accelerator. They were quite clever, refusing to re-engage the clutch if you tried to change down from unwisely high revs, but ultimately automatic drivers preferred regular hands-off autos, and manual drivers preferred having a clutch for full control.

CVT automatic gearboxes

CVT stands for continuously variable transmission. While there are a few different mechanical variants of CVT (the most familiar using the motion of a belt or chain between cone-shaped input and output pulleys), the effect is largely the same in all: a continuously variable, stepless gear ratio that adjusts to best match road speed with engine speed.

CVTs are very smooth, with no distinct gear changes, but not everyone gets on with the strange rise and fall of engine revs independent of road speed. Some manufacturers introduce artificial steps into CVTs to make them feel more like conventional automatics to alleviate this disconcerting feeling.

Read more in our guide to CVT gearboxes…

Electric vehicles

One or two prototypes or homebrew conversions aside, electric cars are almost all automatics by default. From a functional point of view, they’re little different to most of the automatic gearboxes above: put the car into drive and pull away. Due to the way an electric motor works though, EVs tend to use what’s known as a reduction gearbox, which turns high motor revs into more sensible wheel speeds.

Multi-speed EV gearboxes do exist, but most just have one ratio which works all the way from a standstill to the car’s (usually limited) top speed. Some EVs do give you virtual ratios to play with, like the Hyundai Ioniq 5 N, which replicates the feel of a dual-clutch combustion performance car.

Read more about electric car gearboxes in our guide…

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