What are the differences between AT, CVT, DCT, and MT transmission fluids? How to choose the right one for your car?

Not all automotive transmission fluids are the same. A vehicle using an automatic transmission (AT), continuously variable transmission (CVT), dual-clutch transmission (DCT), or manual transmission (MT) may require fluids with very different technical specifications.

Choosing the wrong transmission fluid can affect lubrication, hydraulic control, friction characteristics, and the overall performance of the transmission's internal components.

So, what are the differences between AT, CVT, DCT, and MT transmission fluids? How can you determine the right type of fluid for your vehicle without relying solely on brand, model year, or number of gears?

Let's explore the details with GARTZ.

1. Why does each type of gearbox require specific oil?

The car's gearbox is responsible for transmitting and transforming torque from the engine to the wheels. However, different gearbox technologies use different transmission and control mechanisms.

Gear oil is more than just a lubricant. Depending on its composition, it can also perform functions such as transmitting hydraulic pressure, controlling friction, cooling, and protecting components from wear.

Therefore, you shouldn't choose transmission fluid based solely on color, perceived viscosity, or the assumption that all automatic transmission fluids are interchangeable.

Key principle: Gear oil must meet the specific technical requirements of the gearbox being used.

2. Table differentiating transmission fluids for AT, CVT, DCT, and MT transmissions.

This table helps identify technology groups, it is not a direct conversion table between oil products.

3. What is AT (Automatic Transmission Fluid)?

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Illustration of the Toyota A240E automatic transmission (AT). Source: Wikimedia Commons – CC0.

AT stands for automatic transmission with gears. In many popular car models, AT transmissions use a hydraulic torque converter combined with planetary gears and internal clutches.

ATF oil can simultaneously perform the tasks of lubrication, cooling, hydraulic pressure transmission, and friction control during gear shifting.

Why does ATF oil need to meet the correct standards?

Automatic transmissions (ATs) are designed with different requirements regarding viscosity, friction characteristics, operating temperature, and control system performance.

For example, two cars using the same 6-speed automatic transmission don't necessarily mean they use the same type of ATF. Similarly, it's not possible to assume that all 8-speed transmissions use the same type of oil.

To determine the appropriate ATF, you need to check the transmission code, the manufacturer's oil specifications, and the relevant technical documentation.

Gartz AT transmission fluid lines

GARTZ currently offers a range of automatic transmission fluid products with different grades:

GARTZ ATF G4– This ATF fluid is designed for previous generation automatic transmissions.

GARTZ G6– The ATF oil range is designed for applications with specific technical requirements.

GARTZ ATF G8+– Fully synthetic, low-viscosity automatic transmission fluid for certified applications.

GARTZ 6HP– This product line is geared towards ZF 6HP gearboxes and suitable applications.

GARTZ 7G-Tronic– The 7G-Tronic oil range for various applications has been announced.

GARTZ 9G-HP– A range of oils for modern automatic transmission applications, according to the technical specifications.

Each product must be compared against OEM requirements and compatibility documentation before use.

4-speed + 3-speed transmission fluid

Note: The names G4, G6, G8+, or 9G-HP do not mean that simply knowing the number of gears in the transmission will allow you to immediately choose the corresponding product.

4. What is CVT (Continuously Variable Transmission Fluid)?

What is a CVT vehicle? An explanation of the differences between CVTs and AT vehicles, as well as their advantages and disadvantages - SOMPO CAR MAGAZINE | [Official] Sompo Japan

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Cross-section image of a Toyota Super CVT-i continuously variable transmission, illustrating the pulley and belt. Source: Wikimedia Commons – Public Domain.

CVT stands for continuously variable transmission, capable of constantly changing gear ratios instead of shifting between fixed gears like many automatic transmissions (AT).

In common mechanical CVT designs, the system uses a belt or chain drive to transmit power in combination with pulleys of varying working diameters.

CVT fluid plays a crucial role in lubricating, controlling friction, cooling, and supporting the operation of hydraulic systems.

Why shouldn't you use ATF oil instead of CVT oil?

The friction requirements of pulley-belt or chain drives differ from those of clutches in traditional automatic transmissions.

Using oil that does not meet design specifications can affect power transmission and pressure control, increasing the risk of abnormal operation or wear.

For vehicles requiring specialized CVTF oil, the correct specification specified by the manufacturer must be used.

Are CVT and e-CVT in hybrid vehicles the same thing?

This is a very confusing point.

Some e-CVT systems in hybrid vehicles use a planetary gear set in conjunction with an electric motor, rather than operating on belts and pulleys like traditional mechanical CVTs.

Therefore, it should not be assumed that all vehicles with "CVT" in the transmission name use the same type of CVT fluid.

Gartz CVT oil lines

In its range of continuously variable transmission (CVT) fluids, GARTZ currently offers:

GARTZ CVT RED– CVT transmission fluid.

GARTZ CVT GOLD– Premium CVT transmission fluid.

The choice between CVT RED and CVT GOLD should be based on OEM standards and the specifications of each product.

It should not be assumed that service vehicles, vehicles with high mileage, or vehicles with a whining noise necessarily require the use of one of the two products. These cases require thorough technical inspection and compatibility confirmation before oil changes.

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5. What is DCT (Dual Clutch Transmission Fluid)?

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Illustration of a Volkswagen DQ200 dual-clutch transmission. Source: Wikimedia Commons – Public Domain.

A DCT is a dual-clutch transmission that uses two clutches to control the gear groups, allowing for faster gear changes.

DSG is a trade name for dual-clutch transmission technology, commonly found in vehicles from the Volkswagen Group.

However, not all DCT or DSG transmissions have the same construction and oil requirements.

Distinguishing between wet clutch and dry clutch DCT

DCT wet clutch

The clutch operates in an oil-based environment. Depending on the design, the oil can simultaneously control friction, lubricate gears, cool, and support the control system.

These gearboxes often have specific requirements regarding the friction properties and heat resistance of the oil.

DCT dry clutch

The friction surfaces of the clutch are not immersed in oil. However, the gears and control system may still require separate lubrication or hydraulic fluid.

Therefore, it cannot be concluded that all dry-clutch DCT transmissions use DCTF, or that they do not require oil changes.

How to choose the right DCT oil

Before changing the oil, it is necessary to identify the transmission code (DCT/DSG), clutch type, number of oil chambers, and corresponding oil standard.

Some gearboxes have multiple oil chambers with completely different requirements. Using the same type of oil for all chambers may not be in line with the design.

Gartz's DCT/DSG oil lines

GARTZ currently offers the following products:

GARZ DCTF– Dual-clutch transmission fluid.

GARTZ DSG Fluid– DSG transmission fluid conforms to published technical specifications.

Both products need to be matched against each specific transmission code and specification. One product should not be applied to all DSG, DCT, or Powershift transmissions.

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6. What is MT (Manual Transmission Fluid)?

File:Manual Transmission for Volkswagen Golf.jpg - Wikimedia Commons

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Diagram showing the structure of a Volkswagen Golf manual transmission, illustrating the gear assemblies and drive shafts. Source: Wikimedia Commons – Public Domain.

MT stands for manual transmission, which typically uses gear pairs, a drive shaft, and a synchronizer to perform gear changes.

Unlike many automatic transmissions, the driver actively controls the clutch and selects the appropriate gear.

Manual transmission (MT) fluid primarily lubricates gears and bearings, protects load-bearing surfaces, and supports the operation of the synchronizer, if present.

Are all manual transmission fluids the same?

Are not.

Depending on the gearbox design, manufacturers may require different viscosity and performance levels, such as specialized MTFs or gear oils according to specific technical specifications.

For example, SAE 75W-85 is a viscosity grade, not proof that the oil is compatible with all manual transmissions.

Similarly, replacing API GL-4 oil with GL-5 should not be based on the assumption that a higher performance level is always better. The synchronizer requirements and transmission design must be checked.

Gartz manual transmission fluid

GARTZ currently has products GARTZ MT 75W85.

This product belongs to the manual transmission fluid category and its viscosity and technical specifications must be checked before selection for each vehicle model.

7. A 5-Step Guide to Choosing the Right Transmission Fluid for Your Car

To minimize the risk of choosing the wrong oil, car owners and garages can follow this procedure:

Step 1: Identify vehicle information. Note the make, model, year of manufacture, engine version, and distribution market. The same vehicle name may have multiple transmission configurations.

Step 2: Look up the VIN and transmission code. Use the VIN number in conjunction with the relevant technical documentation to determine the transmission code. For vehicles that have had their transmissions replaced, the currently installed transmission assembly must be inspected directly.

Step 3: Confirm OEM specifications. Look up the oil type, technical code, or part number required by the vehicle or transmission manufacturer.

Step 4: Verify the GARTZ oil product. Check the technical documentation, oil characteristics, and confirmed application list. It is important to distinguish between a product that claims to meet technical requirements and one that has been officially approved by the OEM manufacturer.

Step 5: Change the oil according to the correct procedure. Follow the specified oil level, oil temperature, filter change procedure, and any related technical requirements specified by the manufacturer.

The oil change interval should be based on the maintenance guidelines applicable to each vehicle and actual operating conditions. There is no single mileage benchmark that applies to all types of transmissions.

8. Is the jerking, whining, or slow gear shifting caused by the transmission fluid?

Symptoms such as shaking, whining noises, slow gear changes, difficulty engaging gears, or slow engagement of D/R are signs that the transmission system needs to be checked.

The cause could be related to oil level, oil quality, control system, clutch, hydraulic pressure, mechanical parts, or other technical issues.

Changing the oil is not a guaranteed solution to all issues like jerking, whining, or gear shifting delays.

For vehicles exhibiting unusual symptoms, garages should diagnose the cause before deciding on maintenance or repairs.

9. Frequently Asked Questions about AT, CVT, DCT, and MT Transmission Fluids

Can ATF oil be used in CVT transmissions?

Do not attempt to replace the oil yourself. Only use the correct type and standard of oil as specified in the transmission manufacturer's technical documentation.

Does a car with a 6-speed gearbox have to use a GARTZ G6?

That conclusion cannot be drawn. It is necessary to identify the transmission code and OEM oil standard before selecting a product.

Does a dry-clutch DCT require transmission fluid?

Oil may still be needed for the gears or control system. Specific requirements depend on the design of each gearbox.

Do manual transmission cars need regular transmission fluid changes?

You should check the manufacturer's maintenance manual. Manual transmissions may still require oil checks or changes based on time, mileage, or operating conditions.

Do hybrid vehicles using e-CVT use conventional CVT fuel?

This shouldn't be assumed. Some e-CVTs have a completely different structure from belt-driven CVTs and require precise oil specifications to be checked.

10. GARTZ – Selecting transmission fluid according to specific technical requirements

Each gearbox technology has its own operating principle and lubrication requirements.

Understanding the differences between AT, CVT, DCT, and MT is the first step. To make the right choice, a crucial step is needed: identifying the transmission code and comparing it to the OEM standard before selecting the oil.

GARTZ offers a catalog of transmission fluids categorized by technology groups, serving the needs of vehicle owners and garages for information, maintenance, and reference.

Not sure which type of transmission fluid your vehicle needs?

Please send GARTZ the vehicle model, year of manufacture, engine version, and transmission code or VIN via our private consultation channel.

The GARTZ team will assist in cross-referencing technical information and verifying product suitability within the existing catalog. Cases lacking sufficient documentation will be clearly communicated before any recommendations are made.

Check transmission fluid levels with GARTZ

View the complete GARTZ gearbox oil catalog.

Hotline: 0981 125 189

GARTZ – Choose the right oil according to your transmission specifications.