What is a dual-clutch transmission?

What is a dual-clutch transmission? A dual-clutch transmission (DCT) is a sort of multi-speed car transmission system that uses two distinct clutches for odd and even gear sets. The design is frequently compared to two independent manual gearboxes, with their individual clutches enclosed within a single housing and functioning as a single unit. Unlike a manual transmission, the DCT operates as an automated transmission in automobile and truck applications, requiring no input from the driver to change ratios.

Despite the absence of a clutch pedal, a dual-clutch transmission is difficult to categorize as an automatic. While most automatic transmissions employ a torque converter or, in the case of a CVT, a system of pulleys, the dual-clutch gearbox, like a manual transmission, uses clutch plates. Because of how a dual-clutch transmission is set up, driving it like an automatic transmission will almost certainly result in a poor driving experience and may even cause significant transmission damage.

Understanding how a DCT works and the benefits and drawbacks of this gearbox style can assist extend the life of the transmission and improve the overall driving experience.

ZF 8-speed dual-clutch transmission

What is a dual-clutch transmission?

Because automatic transmissions are convenient, “manumatic” or semi-automatic gearboxes have grown increasingly popular among enthusiasts. However, semi-automatic transmissions don’t all have the same purpose in mind. This transmission has a dual-clutch setup.

A dual-clutch transmission has at least two clutch discs, one for even-numbered gears and odd-numbered gears. Rather than relying on the driver to instruct it to shift gears, the dual-clutch transmission automatically shifts. Most vehicles with a DCT also feature a manual mode, and you may utilize a manual gear changer if you’d like. That such, DCTs are a mix of an automatic and manual transmission.

In most cases, shifting is automatic in a DCT transmission. However, many people say it is a manual because it still uses a clutch plate and gear shifting is similar to a manual.

As far as we’ve come to know how cars’ transmissions work, the problem is that we’ve eliminated the portion of the equation that should apply to the driver. For example, a dual-clutch transmission and a continuously variable transmission (CVT) are the same, as they both allow drivers to make changes on the fly. This underscores the issues with making generalizations about all transmissions, as this assertion shows.

What is the difference between a “wet” and “dry” dual-clutch transmission (DCT)?

Of all the DCT models, the most crucial distinction is whether or not it’s a wet or dry clutch. Wet clutch dual transmissions mean that oil is used to help disperse the heat that builds upon the clutch plate.

Dual-clutch transmissions are more widespread and come with many benefits. They are lighter than a wet dual-clutch transmission, have drag, and because they are “dry,” they are less likely to leak transmission fluid or splash. However, because there is less lubrication, they are more prone to overheating.

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What are the advantages and disadvantages of dual-clutch transmissions (DCT)?

Dual-clutch transmissions come with some benefits. The most significant is that it is quicker and more fuel-efficient than either a manual or automatic transmission. However, they also come with disadvantages. Among them, they take some getting used to, can be twitchy, and feel as though they have turbo lag. It is also only within the past few years that they are available in production vehicles. As a result, there are not many vehicles that come with a DCT from the factory.

Advantages of a dual-clutch transmission

  • They shift faster
  • They are more efficient
  • They offer better fuel consumption
  • They offer the freedom to shift or relax

Disadvantages of a dual-clutch transmission

  • They take some getting used to
  • They can drive “jerky”
  • Few vehicles offer dual-clutch transmissions
  • They are expensive to replace

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How do you drive a vehicle with a dual-clutch transmission?

Dual-clutch transmissions are a hybrid transmission system, and as such, they have several techniques that may be surprising and new to either manual or automatic drivers.

Don’t inch forward in traffic.

When traffic is at a standstill or when you’re waiting for a light to change, many people will creep ahead. To gain six feet a year, you need to keep your foot hovering above the brake and crawl in modest increments. Honestly, the only benefit is a habit, but it can damage the vehicle with a dual-clutch transmission.

It would help if you adopted the waiting-until-you-have-enough-space mindset when you drive a DCT vehicle because of the manual driving tendency. Otherwise, you’re “slipping the clutch,” which can wear down the clutch wheels.

A DCT transmission can creep forward. Thus, if necessary, do not delay. Inching up is a simple habit to break, and there are no consequences whatsoever. We promise that those centimeters won’t amount to much, and you’ll get to your destination at the same time.

No need to shift into neutral

In a car equipped with a manual transmission, many drivers will put the vehicle into “neutral” when stopped, putting the car into gear moving again. However, like a vehicle equipped with an automatic transmission, there is no need to take the car out of gear as a DCT transmission will force the clutch to disengage when it feels the brake pedal is applied.

Use your brakes

Dual-clutch transmissions don’t use a torque converter. They use clutches. As with a manual transmission, you wear down the clutch when you use it. As a result, you should use the brakes as much as possible.  

If you’re used to driving an automatic, you’ve probably been stuck on a modest hill with nothing but your torque converter keeping you in place. Torque converters are designed to handle such situations. However, using the clutch to keep the car in place on a hill will wear down your clutch. Use your brakes instead.

Every car comes with a parking brake, including those with a dual-clutch transmission. Use it instead of the clutch to keep your vehicle in place when parked.

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Wrapping it all up

Vehicles equipped with a dual-clutch transmission from the factory are few and far between compared to the prevalence of automatic transmissions. Cars equipped with DCT are performance-oriented, including such cars as:

One manufacturer not represented on this list is BMW. They announced in January 2021 they were discontinuing the use of their dual-clutch transmission, opting instead for an automatic 8-speed transmission from ZF.

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