Which automatic transmission is the best?

Of the three main automatic transmission types – namely, a dual-clutch transmission (DCT), continuously variable transmission (CVT) and a torque-converter automatic – there’s often plenty of debate among car enthusiasts over which his best.

In short, DCT is the best for keen drivers. Hands down.

Assuming you don’t drive a manual, which would be a shame, because manuals are actually the best and most gratifying to drive, DCT is the best way to send torque to your drive wheels.

Why? Because they are most similar to a manual. In a way, they are a better than a manual, like two manuals side by side…

‘Two manuals side by side with two clutches,’ you say, ‘but I only have one foot for the clutch…’

Imagine you have a mate in the passenger seat; you nominate them to be responsible for odd gears (1, 3, 5, Reverse), and you nominate yourself for even gears (2, 4, 6).

You can’t both have a gear engaged at the same time, so when they’re in first, you are holding your clutch in. When you are in second, they’re holding their clutch in.

DCTs do away with mates in the passenger seat and replace them with wet clutches and transmission control units.

The computer selects the gear you are in, and preselects the next gear it thinks you will use based on how you are driving, but leaves the clutch open on that gear until you (or the auto mode) actually shifts.

I used to be based with McLaren’s test team at the IDIADA proving ground in Spain. Quite often, we’d be testing at a racetrack named Castelloli near Montserrat, an incredible mountain near Barcelona.

On the road out to the track there are quite a few tunnels. And what do you do when you are driving a supercar in a tunnel? You boot it of course! The cars sounded amazing and the gear changes, with the accompaniment of exhaust popping and banging, sounded even better.

They sounded different depending on which powertrain mode you were in. Normal mode was fairly sensible, a quick shift, but smooth. Sport mode was ignition cut. The shift was slipped between the misfiring of a few cylinders with loud backfires when the ignition firing was switched back on.

Race mode was inertial push. In this mode the engine was left at full song and the clutch in your next gear was slammed shut. The inertia of the engine plus all the power it was producing was enough to do chirpies in fourth gear at 200km/h in a McLaren P1.

The engine wasn’t cut so there were no symphonics but the kick in the back was more than enough to let you know you were alive.

A CVT is like a transmission with an infinite number of gears, which is constantly changing. Like DVT (deep vein thrombosis), they are best avoided. Unless you are driving a Koenigsegg hypercar.

That’s right, the Swedes figured out a way to make a car accelerate from 0-100 in 2.8 seconds, and travel at 410km/h all with one gear.

To do it, they use a hydraulic CVT (basically a locking torque-converter), with an engine and two rear-wheel electric drives, and a final drive set for seventh gear.

Other, more sensible, less cool cars use CVTs. Typically hybrids. The idea is, with a constantly variable transmission you can always keep the car in its most efficient rev range.

These normally work with a belt running on two opposing cones, oriented head to toe. If you slide the belt one way, it goes up gears; if you slide it the other, it goes down gears.

Despite the efficiency advantages, CVTs aren’t commonly used because they’re not particularly well liked. In fact, some hybrid vehicles mimic gear changes just to give people a more familiar feeling.

Aah, the good, old fashioned torque-converter automatic gearbox. What used to be the fallback option for people with two left feet and who couldn’t drive manuals has become the go-to for Aussies.

Europeans and Brits can’t stand them, and I don’t blame them. Sure, they are easy in stop/start traffic, but they are lifeless on the open road.

They are less efficient than their CVT and DCT counterparts to boot, with the hydraulic torque converter converting torque into wasted heat.

Adding to that, tradies everywhere are in revolt at how bad the auto trans calibrations are.

They kick down at the drop of a hat, and are always hunting for a gear with the tyranny of choice of having too many gears.

My uncle’s EA Falcon had a new four-speed auto. The latest Ford Ranger has 10 gears. Overkill?

So, there you have it. If you can’t drive a trusty and enjoyable manual, the DCT would be my weapon of choice.

That said, most cars don’t come with a choice of transmissions, and while I’d prefer DCT, I wouldn’t rule out a traditional auto if the car I liked only came with one.

Paul Batten is a race and rally driver and a former senior vehicle dynamics engineer for McLaren Automotive and, prior to that, Prodrive/Ford Performance Vehicles. He is also the founder of www.LifeMapp.app.