How Does a Dual-Clutch Transmission (DCT) Work?

The Function of a Dual-Clutch Transmission

Market Technology before it’s ready!

John Baker|Jan 02, 2020 11:43 AM

A dual-clutch transmission (DCT) is synonymous with high performance. Compared to a traditional automatic transmission, it delivers…

Faster, smoother shifts
Increased fuel economy
Improved performance
Surprise breakdowns (well they’ll solve that soon)

Although the DCT transmission dates to the 1930s, it made its first practical appearance decades later in several 1980s-era race cars.

In 2003, the Volkswagen Golf Mk4 R32 was the first production vehicle to feature the technology.

Today you can find a DCT in a variety of cars, from the relatively tame Hyundai Sonata to the brash, sexy Nissan GT-R.

How a DCT transmission works

DCTs are essentially two manual transmissions working in tandem.

One gear shaft contains the even-numbered gears, and the other contains the odd-numbered gears. While you’re accelerating in first gear, for example, the computer selects second gear on the other gear shaft. When it’s time to up-shift, the clutch that controls the even gears disengages and the clutch that controls the odd gears engages.

Compared to a traditional automatic transmission, gears shift much more quickly and smoothly in a DCT transmission – the perfect complement to a powerful, high-performance engine.

While DCTs are capable of seamless shifts, they can suffer from shudder or lurching at slow speeds.

Transmission fluid with specific frictional properties is required to prevent shudder. DCT fluid must also maintain the proper viscosity to provide protection during the high-heat operation native to high-performance sports sedans and supercars.

100% Synthetic Dual-clutch Transmission Fluid (DTC)

Buy AMSOIL DCT Fluid

Protect the thrill

AMSOIL 100% Synthetic DCT Fluid is specifically engineered for sophisticated dual-clutch transmissions.

Its superior frictional properties protect against shudder and gear clashing to consistently produce fast, smooth shifts. When you are waiting on the light you need a fluid engineered to solve the “constant slip mode” which is occurring to work as if it had a torque converter. Slight engagement while you are on the brakes requires beyond expectations technology you only can expect from AMSOIL.

AMSOIL Synthetic DCT Fluid’s exceptional durability provides stability in stop-and-go traffic and excels under intense, high-heat conditions. Its built-in oxidation resistance helps prevent sludge formation in vital transmission parts.

Available in our 98th St store. Just behind the Marlins at the Tea exit. Exit 73 Sioux Falls.

Lookup Your Vehicles

What is a CVT Transmission?

CVT Transmission? How Does It work?

John Baker|Mar 27, 2019 11:18 AM

“CVT” stands for continuously variable transmission. A CVT transmission uses a pair of variable-diameter pulleys and a belt or chain to provide unlimited gear ratios.

How does a CVT work?

To illustrate, think of a traditional automatic or manual transmission. They’re built with a defined number of gears, for example first through sixth (plus reverse). The transmission can operate in only one gear at a time. You typically feel a slight surge with each gear change.

CVTs, however, offer unlimited gear ratios.

Take a look at the image. You can see the metal belt connecting the two pulleys. Depending on engine speed and load, the computer automatically varies the pulley sizes to ensure the optimal gear ratio for the driving conditions.

CVT transmission pros and cons

What good does that do?

Imagine pedaling a bike. As you approach a steep hill, you adjust the shifters so a smaller chainring attached to the pedals is driving a larger sprocket on the rear wheel. This reduces the effort required to move the bike.

When you reach a stretch of flat road, you adjust the gear ratio again so a larger chainring attached to the pedals is driving a smaller sprocket. This helps achieve the perfect balance between energy expended and bicycle speed.

The same principle applies to a CVT, except the computer does all the thinking for you. When starting from a dead stop, it varies the pulley diameters (smaller drive pulley and larger driven pulley) so the engine can move the car as efficiently as possible. As you accelerate, it continuously varies the pulley sizes to keep the engine in its “sweet spot,” which results in improved fuel economy. Plus, you never feel the gear engagements because, in effect, there aren’t any.

CVTs gaining in popularity – but there are negatives

These benefits are why many car makers, including Nissan, Honda and Toyota are introducing more vehicles with CVTs.

There are drawbacks, however, including the “rubber-band effect” (you rev the engine, yet it takes a moment for vehicle speed to catch up) and lack of driver involvement (zero fun). In addition, most CVTs’ relatively diminutive parts can’t handle the power and torque of the truck or SUV you use to tow your boat or camper, which is why you find them mostly on smaller cars. Although there are some exceptions, as the list shows, which shows popular vehicles with a CVT.

What cars have a CVT transmission?

Honda Accord
Honda HR-V
Mercedes-Benz A- and B-Class
Nissan Altima
Nissan Pathfinder
Subaru Forester
Subaru Impreza
Subaru Legacy
Subaru Outback
Toyota Camry
Toyota Highlander Hybrid
Toyota Prius

Slip into something special

One look at the guts of a CVT and you can’t help but wonder how the belt doesn’t just slip wildly over the pulleys.

Believe it or not, the transmission fluid plays a major role in ensuring the belt or chain remains in contact with the pulleys without slipping.

That’s why CVTs require specialized CVT transmissions fluids, and not the traditional automatic or manual transmission fluid you probably have in your garage. CVT transmission fluids must be formulated with the correct frictional requirements to guard against slipping. Using the wrong fluid will reduce performance and potentially wreck your transmission.

Wear protection also important

Solid wear protection is also vital to maximizing CVT performance and life. That’s why we designed AMSOIL Synthetic CVT Fluid to fight wear and help extend transmission life.

To demonstrate, we pitted AMSOIL Synthetic CVT Fluid against Nissan NS-2 CVT Fluid in a field trial. After 100,000 miles, the belt lubricated with AMSOIL Synthetic CVT Fluid demonstrated minimal wear, as you can see in the images. This helps you get the best performance and most life out of your CVT.

The belt lubricated with Nissan NS-2 CVT Fluid demonstrated increased wear.

Buy AMSOIL Synthetic CVT Fluid

While driving purists may initially scoff at the notion of a transmission that requires no driver input, many eventually warm up to CVTs’ increased gas mileage and smooth operability.

If you’re one of them, make sure you protect it with a good CVT transmission fluid.

Category: Transmissions