DCT Transmissions Explained

Dual-clutch transmissions, or DCTs, have become increasingly common in mid- to high-end performance and luxury vehicles over the past few decades. Originating from the rapidly changing world of motorsports, dual-clutch transmissions allow for the control and engagement of a manual transmission with shifts often faster than most automatics.

What is a Dual Clutch Transmission?

As the name implies, DCTs prioritize a pair of clutches to perform. One of these clutches handles the odd gears (first, third, fifth, and reverse) while the other handles the even gears (second, fourth, sixth). The use of two clutches to control one gearbox allows for one clutch to disengage to shift while the other maintains connection with the gears, which allows the vehicle’s computer to complete the next shift before the last gear even disengaged.

While DCTs allow for manual shifts, they don’t require the driver to use a clutch pedal, as the computer automatically controls the engagement and disengagement of the clutches. DCTs use computerized predictions to begin the next shift before the driver even asks for it, using factors like the rate of acceleration/deceleration and current engine speed to complete shifts prior to the other clutch disengaging.

Benefits of DCTs

Dual-clutch transmissions provide several benefits over traditional automatics and manuals, including:

Superior shifting performance

Seamless gear changes

Reduced drivetrain power loss

Increased acceleration

Improved efficiency

Manual control with automatic speed

Common Problems with Dual-Clutch Transmissions

While DCTs bring a host of benefits to the table, the increased complexity and number of moving parts can also lead to issues that you should know.

Jerkiness at Low Speed

Some dual-clutch transmissions, especially earlier versions, may experience rough shifting at low speeds. This often occurs due to the transmission struggling to balance clutch engagement, which can lead to an annoying transmission feel during everyday driving.

Clutch Wear

As a result of constant clutch use within DCTs, clutch wear is a crucial factor to be aware of. Worn clutches may cause the transmission to fail to properly engage with the gearbox, leading to symptoms such as clutch slippage, rough shifting, and other transmission operation issues. When clutches wear down or fail, you’ll likely require a clutch replacement to remedy the issue.

Software Malfunctions

DCTs rely on the vehicle’s internal computers to control shifting and the clutch. When this computer experiences software failures, it can disrupt the transmission’s ability to change gears at the proper time. Software failures can lead to similar harsh shifts and unusual feelings as the other problems listed.

Increased Repair Complexity/Cost

One of the most significant downsides of DCTs is their increased complexity and number of moving parts, which not only allows for more potential points of failure but also may lead to more expensive repairs than traditional transmissions. Much of this complexity comes from the addition of a second gearbox and clutch, and some components require specialized equipment and training to carry out properly.​

Unusual Noises & Vibrations

Some DCTs may exhibit unusual sounds or vibrations through the chassis when driving, particularly at lower speeds. This doesn’t always mean there’s an issue to be worried about, as this can be a normal behavior of some DCTs. If the sound/vibrations worsen over time, it’s important to have your transmission inspected by a trusted professional to ensure your transmission is operating as it should.

Transmission Services in Austin, TX

Get your transmission repair services started right with our service experts. Every quality auto repair starts with an accurate diagnosis from a qualified technician. Whether you drive a vehicle with a CVT, DCT, or a traditional manual or automatic transmission, the team at Edgestone Automotive maintains a commitment to excellence with all auto services, including its transmission repairs.