You know on a car that a gearbox is a device that transfers the energy of the engine (or motor, if you’re in an electric vehicle) to the wheels to propel you down the road, but you’re also aware that there are multiple different types of gearbox – and we’re talking about more than just straight-up manual versus automatic here. So allow us to walk you through the various different types of car gearboxes, and then let us help you choose which one is the right fit for your lifestyle.
How Does Manual Work?
Simplest one of all to explain, most involved one to operate. This is your traditional manual gearbox, complete with what is known as a H-pattern shift lever and three pedals in the driver’s footwell – the throttle to the right, the brake in the middle and then a clutch pedal to the left. The clutch is intrinsic to a manual-car driving experience, as you need to depress and then release the left-hand pedal every time you want to change gear. This process disengages the clutch from the gears as you press down on the pedal, allowing you to switch gears with the H-pattern lever, and then you release the clutch pedal to re-engage the clutch itself, restoring drive from the engine to the wheels.
To this end, there’s a process of balance between throttle and clutch for every gearchange, which is required to drive smoothly and prevent stalling the engine – something which is impossible in automatic cars. Also, manual vehicles are not as easy or comfortable to drive in slow-moving or city-based traffic.
In truth, a manual gearbox is becoming an increasingly unpopular choice for modern cars, most of which are specified as automatics, but driving enthusiasts still prefer the interaction that comes of having a manual car – to drive one well necessitates a certain level of skill and touch. This is why manual gearboxes are increasingly becoming something you’ll only find on dedicated sports vehicles and high-performance machines, where a demanding clientele still want 3 pedals in their driver’s footwell.
Manual gearboxes on most post-war cars have had at least 4 forward gears and 1 reverse. In the 1980s, 5-speed manuals became more common, then 6-speed units started to arrive in the 1990s and through the 2000s – most manual cars sold today will have a 6-speed gearbox, unless it’s a very basic city car or supermini with a low-powered engine, where 5-speed ‘boxes are still employed. In the Porsche 911 line, there is even a 7-speed manual gearbox option on Carrera S/4S and Targa 4S models, although this is a rare configuration.
How Does An Automatic Torque Converter Work?
Also known as: Tiptronic, Steptronic, Geartronic, xG-Tronic, EATx, PowerShift (‘x’ = number of gears in question)
From this point on the list onwards, every gearbox option only has 2 pedals in the footwell – the throttle and brake. On every type of automatic, advanced control mechanisms perform any required gearshifts automatically (hence the name for this type of transmission) and the driver needs do nothing more than select ‘D’ in order for the vehicle to move forward, or ‘R’ to go backwards.
Automatics with standard, transmission-tunnel-mounted levers normally have what is called a ‘P-R-N-D’ layout of the various options available – these are Park, Reverse, Neutral and Drive, and they do what they say on the tin. Other arrangements include the column shift – where the drive lever is mounted on the steering column; popular on many American cars of old, but still seen on modern-day Mercedes-Benzes – and button-shifts, employed by Aston Martin, where the P-R-N-D functions are presented on separate switches on the dashboard. You sometimes see these button-pad ‘boxes on other automatic types (dual-clutch, CVT) from manufacturers like Hyundai and Honda.
The standard torque-converter automatic is one of the older types of self-shifting transmission and it’s easily the most commonplace in automotive history. It uses a fluid coupling (the torque converter) to translate drive from the engine to the wheels, so there is no physical clutch plate as there is in the manual car. More modern versions use a lock-up torque converter, which bypasses some of the traditional drawbacks of the older hydraulic units – such as increased fuel consumption, slower gearshift times and greater repair expense when they go wrong.
Automatics are simple to use and ‘true’ torque-converter units are most commonly found on big executive cars, like the Audi A8, BMW 7 Series and Mercedes S-Class, as well as some very high-output cars – this is because torque converters can typically handle more torque than other types of transmission. A good example of a rapid car with a torque converter is Audi’s RS6 Avant, which has a Tiptronic gearbox and not an S tronic (see ‘Dual-Clutch’, below).
Torque converters have the broadest spread of ratios of any gearbox type. In antiquity, 2- and 3-speed units were commonplace, the latter right up to the 1970s – when big Mercs employed them on their V8s. Meanwhile, Rolls-Royce was still using a 3-speed auto right up until 1991. Since the 1980s and 1990s, 4- and 5-speed automatics have appeared, but it wasn’t until 2002 that the world’s first 6-speed automatic was used on the E65 (4th-generation) BMW 7 Series. We have since had 7-, 8-, 9- and even 10-speed automatics launched onto the market – 8-speed units are now the most commonplace throughout the industry, as they offer excellent fuel efficiency and a good spread of ratios, but examples of 10-speed self-shifters can be found on the Ford Ranger 2.0-litre biturbo diesel and Mustang V8 petrol cars, as well as the Lexus LC luxury coupe.
How Does An Automatic Dual-Clutch/Multi-Clutch Work?
Also Known As: DSG, DCT, PDK, AMG Speedshift, MCT, EDC, PowerShift
This is the most confusing one. As its name suggests, the dual-clutch transmission has at least 2 clutch plates, hence its name. And the minute you’ve got actual physical clutch plates involved, then technically you’re talking about a manual – correctly speaking, a dual-clutch transmission would be best specified as a robotised manual, rather than an automatic.
However, as every single dual-clutch system has a fully automatic ‘D’ mode, just like a torque converter, then people tend to refer to them as ‘autos’ these days. The twin-clutch system has faster shift times than a trad torque converter, mainly because it has 1 clutch controlling odd-numbered gears (1, 3, 5 and 7) and another handling the even-numbered cogs (2, 4, 6 and reverse, usually). In the simplest possible terms, if you are travelling along in, say, 4th and you’re preparing to shift up, the gearbox has already got 5th ‘pre-selected’ with the next clutch. Control software then simply switches from one clutch to the other to make the shift as fast and as seamless as possible.
Dual-clutch units are perceived as sportier than ‘full’ automatics and normally come on high-performance cars, meaning you get paddle shifts on the steering wheel to allow you to change gears when you want to. Most ‘boxes of this type have 6 or 7 speeds, but an 8-speed PDK is already in service in some Porsche models and the Honda NSX hybrid supercar uses a 9-speed transmission.
The flipside of dual-clutch units is they can be very expensive to repair if they ever break, while they don’t always offer ‘creep’ like a torque-converter automatic. This is a feature on autos where, as soon as you come off the brake pedal, the torque of the engine starts to move the car forward slowly without you having to touch the throttle. This is useful and relaxing in heavy stop-start traffic, but not all dual-clutch units will do the same thing – they often require the driver to press the throttle to resume motion from a stationary position.
How Does An Automatic Continuously Variable Transmission (CVT) Work?
Also Known As: eCVT, Xtronic, Lineartronic
A controversial one. The CVT is theoretically the best transmission of all. As its name implies, it doesn’t have fixed ratios or cogs like the manual, automatic and dual-clutch units we’ve already mentioned, but instead has – in plain terms – a belt running around a number of drive pulleys. Technically, the CVT has access to infinite different ‘gears’ as it can adjust the belt running round the pulleys according to whether you need acceleration/power or fuel economy.
It is particularly beloved of Japanese manufacturers, especially companies which make hybrid cars, because the CVT allows the engine to operate in its most efficient zone for more of the time than any other transmission type – this aids fuel economy. Not only that, but a CVT is mechanically very simple compared to other gearboxes, which means it is far less likely to malfunction and requires much less in the way of expensive maintenance through its lifetime.
The problem is, a CVT brings in some considerable refinement issues. They have an unusual method of power delivery during acceleration, which makes the engine rev long and high, while there’s a feeling of delay between pressing the throttle and the power making it to the wheels. Some newer CVTs are better at this, either mimicking gearshifts like you’d find in other cars or simply smoothing out the power delivery, but many CVTs can be rather weird to drive.
This is a culture thing, though. Japanese manufacturers love them because they are reliable and efficient in the first place, two qualities the country values highly, but also because Japanese drivers are not as aggressive with the accelerator in the main as we Europeans are – so they tend to encounter fewer drawbacks with the CVT and then are surprised we complain about the transmission type over here. To this end, you’ll find CVTs most readily on Toyotas, Hondas, Nissans and Mitsubishis, but Ford and Renault (as an extension of the French company’s tie-up with Nissan) have been known to use them as well.
How Does An Automatic Reduction Gear Work?
Strictly speaking, any car gearbox is a reduction-gear mechanism in its purest form, but what we’re speaking about here is a new ‘type’ of transmission which is finding favour on electric cars. The plain single-speed reduction gear is employed on most zero-emissions vehicles and basically means one ‘gear’ takes the car from rest to its maximum theoretical top speed. It is this totally linear delivery of power and torque which makes electric cars so accelerative – they do not have to pause between ratios as a gearbox shifts from one cog to the next.
Almost all electric cars, like from the Renault Zoe and Nissan Leaf up to the Polestar 2 and the Teslas, have single-speed reduction gears, although the Porsche Taycan and related Audi E-Tron GT have 2-speed transmissions, which allows for faster acceleration in the 1st and then better cruising manners in the longer 2nd. With reduction-gear transmissions, there is no option to shift for yourself, because there are no different ratios to go through – and this even counts on the Porsche and Audi, which make the swap from 1st to 2nd themselves.
Which Should I Choose?
In the end, much of it will come down to what sort of car you’re looking to buy – many model lines are automatic-only these days, while the CVT is commonly associated with non-plug-in hybrid vehicles from Toyota, Lexus and Honda. You’ll only ever find the pure reduction-gear set-up on electric cars, while the manual and dual-clutch ‘boxes are typically aimed more at enthusiastic drivers.
In truth, while we love the romanticism of the 3-pedal transmission, unless you’re a really keen motorist who’s big into cars, we’d advocate any automatic over a manual. Huge advancements in the refinement, engagement and shift speeds of the latest dual-clutch, torque-converter and CVT systems means they’re good in all departments, and they’re particularly strong choices if you do a lot of town and/or motorway driving.
For our money, a ‘proper’ torque-converter automatic is hard to beat for the smoothness and power delivery it offers, but many prefer the almost imperceptible shifting speeds of a dual-clutch transmission. Therefore, if you want the best modern-day gearbox you can find, try a DSG, DCT or similar out for size.
