With the advent of modern automatic transmissions, the issue of protecting mechanisms and assemblies has become acute. Oils for manual transmissions were unsuitable because their characteristics did not meet the necessary requirements. An automatic transmission, like a mechanic, shifts gears, but the machine operates independently, and this greatly complicates its design. In addition, the operating conditions of the mechanisms and components of the machine do not correspond to the operating conditions of the mechanics, so a new ATF type of lubricant was developed for it.
Lubricant ATF
ATF fluids are special oils used to work in automatic transmissions with a hydraulic transformer, as well as in some models of variators. The abbreviation for lubricants is deciphered as follows: ATF (Automatic Transmission Fluid, automatic transmission fluid). The purpose of the lubricant is to protect the internal parts of the box from corrosion, overheating and wear, in addition, with the help of a liquid, an impulse is transmitted from the transmission power plant. Lubricants are liquid, with increased fluidity, mineral or synthetic base.
The transmission fluid performs the following functions:
- Control and management of automatic transmission;
- Cooling of parts and mechanisms;
- Formation of a protective film on the surface of parts;
- Corrosion protection;
- Prevention of early wear of mechanisms due to friction forces;
- Transfer of impulse from the power plant to the transmission;
- Helps to work friction discs.
Working fluid in mechanical boxes and ATF automatic transmission oil, lubricants that are not similar to each other. ATF fluid performance differs from conventional oil in many ways. To create the desired consistency, mineral oils are used, adding special additives to them. Each automatic transmission is suitable for a certain type of oil, with its inherent set of characteristics. The use of an inappropriate liquid inevitably leads to a breakdown of the mechanism, which is why it is so difficult to find a product similar to the original.
For the first time, the specification for gear lubricants was put into use in 1949. The concern that offered to do this, General Motors, had no competitors and analogues at that time, and ATP fluid was specially developed for the automatic transmission designed by the company. At present, the development and standardization of transmission fluids are carried out by: Hyundai, Toyota, Ford, Mitsubishi, GM.
Types of ATF fluids
The first type of ATF in automatic transmissions was produced by GM, it was called ATF-A. In 1957, a modernization was made and a new fluid appeared under the name Type A Suffix A.
Types of ATF fluids on the market today:
- The Mercon type, developed in 1980, was carried out by automaker Ford. Compatible with other types of lubricants as their characteristics are identical. The difference from competitors is the calculation for the use of fluids in mechanisms where speed is needed when shifting gears.
- Starting in 1968, GM began producing a lubricant called Dexron. The liquid did not tolerate high temperatures, in addition, it was based on whale fat, so production was soon stopped. Since 1972 the type has been replaced by a new fluid called Dexron IIC, however the product was prone to corrode in some parts of the box so it was also replaced with Dexron IID which used anti-corrosion additives. Until 1993, GM produced oil with the prefix IIE, which was famous for its ability to minimize the amount of moisture in the box. GM gained fame with the release of Dexron III fluid in 1993. The product had increased fluidity and performance at low temperatures, as well as improved properties in relation to rubbing surfaces. It is applied to hydraulic boosters and hydraulic systems. In 2005, a new liquid with index IV was released. The product was developed for a six-speed gearbox, has improved performance, extended service life, improved fuel efficiency.
- Alison C-4 grease, used on trucks and construction vehicles.
Especially for automatic transmissions of Toyota and Lexus cars, Toyota has developed ATF WS fluid. It is successfully used in automatic transmissions and automatic transmissions with the possibility of manual shifting. ATF WS Toyota grease is a priority when it comes to its use on cars manufactured by the company.
ATF fluid replacement
Transmission fluid refers to consumables that change periodically. Timely replacement of ATP in automatic transmission increases the service life of transmission parts and mechanisms, because in the process they are subject to increased wear, the products of which settle in the oil.
Conditions affecting the oil change interval:
- Intermediate vehicle mileage between fluid changes;
- The environment and conditions in which the car was operated;
- The nature of operation and driving style of the vehicle.
The design of automatic boxes requires the mandatory removal of the pallet and cleaning the magnets from metal chips and accumulated debris. When changing the oil, the filter element must also be changed to remove impurities and ensure fluid purification in the future.
It is advisable to carry out the procedure at branded service stations equipped with special devices for pumping out residual liquid from the system. Independent operation will allow only a partial replacement of the fluid, which may adversely affect the operation of the unit in the future.
Checking the ATF level in the box
The quality of the performance of functions and the duration of the life of the box directly depend on the level of lubricating fluid in the product. The procedure for checking the oil level is carried out regularly, since the deviation of the established norms entails unpleasant consequences:
- The lack of oil leads to the ingress of air bubbles picked up by the pump, and the rapid wear of the clutches in the future. They also burn, which disables the system.
- An excess of lubricant leads to its leakage through the ventilation valve, which is fraught with the loss of a significant amount of fluid and also the failure of the clutches.
Liquid level control on each box model is carried out in accordance with the requirements. Before performing work, it is necessary to familiarize yourself with the documentation for the product and follow the procedure clearly following the established regulations.
Fluid selection according to ATF specification
- Dexron B: the first specification for ATF fluids, developed in 1967;
- Dexron II: development begins 1973, the standard has received worldwide recognition;
- Dexron IID: beginning of implementation in 1981, designed for automatic transmissions operating at temperatures not lower than -15°C;
- Dexron IIE: launched in 1991, designed for automatic transmissions operating at temperatures down to -30°C. Synthetic base, improved viscosity characteristics;
- Dexron III: Introduced in 1993, designed for use in modern gearboxes, increased requirements for viscosity and friction;
- Dexron IV: Synthetic, packaged in modern boxes.
Ford also has a specification, its name is "Mercon", but the marking has not been widely used, it is unified with the GM specification. For example: DesxronIII / MerconV.
Crysler also specifies its products, the specification is called "Mopar". In our region, it is not common, and if it occurs, it is also unified with Dexron.
Mitsubishi (MMC)-Hyundai classification:
- Type T (TT): used in A241H and A540H all-wheel drive boxes manufactured in the 80s;
- Type T-II: designed for electronically controlled automatic transmissions produced in the early 1990s;
- Type TT-II: electronically controlled automatic transmissions from 95-98;
- Type TT-III: electronically controlled automatic transmissions from 98-2000;
- Type TT-VI: electronically controlled automatic transmissions after 2000;
- ATF WS: A generation of synthetic lubricants used in modern transmissions manufactured by Toyota.
Incorrect selection of the mixture entails a large number of breakdowns, so you must refer to the documentation for the product and follow the recommendations that are written there.
Interchangeability of ATF fluids
Important! Toyota ATF WS is not interchangeable with Toyota and Dexron fluids. WS grease has the ability to absorb moisture, so the storage container is opened once.
If necessary, ATF WS gear lubricant is replaced with third-party oils of similar characteristics: Idemitsu, Aisin, Zic.
When changing the lubricant in an automatic transmission, it must be remembered that modern transmission fluids are a mixture of components in a certain proportion, each of which individually represents the final product. The settings of modern automatic transmissions after 2003 are sensitive to the change of components and take into account their specifics in the process of work. Thus, if there is doubt about the type of old oil, it is necessary to do a complete replacement.
Gearbox oils are a separate group of oils. Automatic transmission oil has a higher viscosity, it uses completely different additive packages than engine oil. Higher requirements are imposed on such an oil in terms of its anti-wear, anti-friction and antioxidant properties, since the service life of the oil in an automatic transmission ranges from 30 - 40,000 km to the entire life of the car. The diverse tasks performed by oil in automatic transmissions place very high demands and restrictions on its properties. Oil cools, lubricates, provides frictional grip and transmits torque. The operating temperature range of oil in automatic transmissions is from 90°C to 150°C. Completely different materials used in automatic transmission friction pairs (steel - bronze, steel-cermet, steel - steel, steel - composite materials) cause the use of different packages of antifriction additives in the oil, which are not always compatible with each other. At the same time, it is necessary to prevent aeration, and as a result, foaming of the oil in the automatic transmission, which occurs when hot oil flows are swirled under pressure. The result of aeration and foaming of the oil is the oxidation of the oil and corrosion of the materials from which the automatic transmission is made. The automatic transmission is a highly loaded unit, during the operation of which part of the energy converted into translational motion is spent on the internal friction of the oil, which leads to its significant heating. As a result, the requirements for oil viscosity in automatic transmissions are opposite: to reduce the internal friction of the oil during the operation of the torque converter, the oil must have a low relative viscosity, and to ensure gear lubrication, on the contrary, the oil must have a sufficiently high viscosity.
Types of oil for automatic transmission.
Three main types of oils are used in automatic transmissions: Dexron, Mercon and MB. This is due to the historical specification for automatic transmission oil. The first oil specification was formulated in 1949 by GM Corporation. At the turn of 1990. the requirements of different specifications have become almost the same so much so that all gearbox oils have become interchangeable. Dexron IV oils are designed for use in automatic transmissions with an electronically controlled torque converter clutch.
GM automatic transmission oil specifications (GENERAL MOTORS)
GM first faced the need to develop and formulate separate specifications for the classification of automatic transmission fluids (Automatic Transmission Fluids - ATF, another name for automatic transmission oil).
ATF type A refers to a type of gear oil that is suitable for automatic transmissions in passenger cars. Oils that passed the tests received AQ qualification numbers. Qualification numbers AQ were assigned under an agreement with GM research center "Amour Research" in the format "Amour Qualification N". Specifications have lost their relevance.
DEXRON (B) - current and current specifications for automatic transmission fluids (automatic transmission oils) GM. Many manufacturers or buyers of such automatic transmissions also use these specifications. The approval is made under the so-called type "B".
DEXRON II, III, IV are the latest specifications for GM oils (automatic fluids). They tighten the requirements for fluids for automatic transmissions. They include and exceed all previous specifications, meet the increased requirements for ensuring environmental safety. Allison Fluids: Type C1 and Type C2 specifications superseded by DEXRON II specifications; "type SZ" - MIL-L-2104D.
FORD Specifications
"Type F" automatic transmission fluids, according to the latest Ford M2C33F and M2C33G specifications, differ significantly from DEXRON oils in some parameters (for example, friction coefficient). The main difference is in the coefficient of friction, which in the case of Ford increases with a decrease in sliding speed, while General Motors, on the contrary, requires a decrease in the coefficient of friction in the same case.
ATF type automatic transmission fluids according to Ford M2C138-CJ and M2C166H specifications can be partially replaced with DEXRON II fluids, however, a complete automatic transmission oil change is most preferable.
Fluids for automatic transmissions of the ATF Dexron II, Plus Dexron III and ATF-A series are designed for transmissions operating under conditions of high mechanical and thermal loads, can be used in transmissions of passenger cars of any automaker, hydraulic power steering and clutch units. Fluids for automatic transmissions of the ATF group are produced under two brands: ATF II D Plus and Dexron III. ATF II D Plus is designed to work in highly loaded transmissions, belongs to the Extrimal Pressure category (extreme pressure). A balanced high-tech additive package provides high anti-corrosion properties. In terms of its parameters, this automatic transmission oil meets the requirements of most of the world's leading automakers. Dexron III is used in automatic transmissions of passenger cars, light commercial vehicles and minivans.
Other specifications.
In addition to the specifications of General Motors and Ford for automatic transmissions, the factory specifications of Chrysler, MAN, Toyota, Allison, Renk, Voith, ZF are used. For vehicles sold in Europe with automatic transmissions manufactured by ZF, automatic transmission oils are selected according to GM specifications. In the automatic transmissions of Audi, BMW and Mercedes of the last years of production, only synthetic automatic transmission oil is poured!
Oil change in automatic transmission.
Changing the oil in the automatic transmission must be carried out in strict accordance with the operating instructions for your car! Violation of oil change intervals, as a rule, leads to a sharp deterioration in the functionality of the automatic transmission and a reduction in its service life. Under severe vehicle operating conditions (driving with a full load, driving with a trailer, frequent engine braking, using vehicles on roads with dirt, sand and snow, high or low ambient temperatures, wheel slip, using the vehicle in start-stop mode (urban traffic jams ), sharp acceleration from a standstill - all automakers recommend reducing the oil change intervals in the gearbox by half. In practice, this leads to a reduction in the service interval for automatic transmission oil in Moscow to 30, maximum 40,000 km! Change the oil more often - your automatic transmission will last longer!
Mixing automatic transmission oils of different types when replacing them.
Mixing is possible, well, it's best to avoid it. To quickly identify the oil poured into the automatic transmission, a dye is added to the oil, the addition of which does not lead to a change in the properties of the oil. However, in conditions where you cannot clearly identify the previously filled oil, it is highly recommended to carry out a complete automatic transmission oil change. The cost of even the smallest repair of an automatic transmission is ten times higher than the cost of a complete oil change in an automatic transmission.
Non-original automatic transmission oil for your car.
When changing the oil in automatic transmissions, some automakers, such as Honda and Mitsubishi, require the use of specialized oils under their brands. It must be understood that neither Honda nor Mitsubishi produce oil on their own, but order its production from leading petrochemical corporations (ExxonMobil, BP, Chevron, PetroCanada, and so on). In addition, information has recently appeared in the press that automakers began to place orders for engine and transmission oils poured into engine units on the conveyor at private factories in Europe (Ravenol, Addinol, and so on) according to their specifications. At the same time, transmission and engine oils produced by Ravenol under its own brand for use in cars, for example, Hyundai and KIA, for the most part of their performance surpass oils produced by the same Ravenol, but distributed in packaging and under the Hyundai brand - the automaker saves money and is not interested in order for the car to work without breakdowns and after the expiration of the warranty period. Therefore, according to experts, the use of oils produced by private European factories directly for use in automatic transmissions of cars of a particular car manufacturer is the best option for those car owners whose warranty period for cars has already expired.
I already touched on the abbreviation "ATF" a little in the article. But today I want to tell you more about it. We will analyze all aspects of the meaning, decoding, why it is categorically different from liquids in a mechanical transmission, how it works. Indeed, there are a lot of questions, there is even such a banal one - is it a liquid or is it oil? Let's figure it out...
Let me start with a definition.
ATF ( Automatic transmission Fluid ) - stands for automatic transmission fluid (automatic). It is used only in "torque converter" machines, also in some CVTs, it is practically not used in robots. It serves to lubricate internal components, as well as transmit torque from the engine - through the transmission - to the wheels.
I read on some forums - what is called the "blood" of the machine, because the liquid is really red.
Oil is not oil?
Let's start with the easiest question, what is oil or not oil at all? Guys, this is a liquid gear oil, it is much thinner than, say, manual transmissions. This is said by many features here, the torque is transmitted using a torque converter, and as we have already dismantled, high pressure is needed - flowing oil. Due to its high fluidity, it is customary to call it a liquid.
For example, gear oils for mechanics have viscosity tolerances and are divided into winter, summer and universal. Often you can see numbers like SAE 70W-85, SAE 80W-90, etc., choose for your weather conditions, but most now use universal ones.
There are no such tolerances on automatic machines! SAE viscosity does not apply to these fluids, they must always remain fluid in any weather, and they must also withstand much higher temperatures than their "mechanical" counterparts. ATF fluids include where there are large loads, this manifests itself in lubrication, protection of components from pollution and oxidation (rust), and also from overheating.
So the mechanics can warm up to 60 degrees Celsius during operation.
But the machine often works with temperatures of 90 - 110 degrees. For example, Chevrolet automatics can heat up to 120 degrees.
Therefore, cooling radiators are installed on the machines so that the oil does not burn at high temperatures. So it's oil, but it's not the same as the other two, mechanical transmission oil and engine oil.
Why bright red?
As we have already discussed from above, ATF oils are not like any other type of lubricant. And therefore it cannot be poured anywhere else, if you mix it up, there can be serious damage. And vice versa - if you pour the usual "manual transmission" into the machine. That is almost instantaneous death. And there were such cases, often they poured engine oil and after a few kilometers the automatic transmission got up.
To avoid such incidents, it was customary to paint the ATF red - that is, this is nothing more than just a difference, nothing more. Well, think for yourself, you will never pour red liquid into the engine, although anything can happen ...
How does it workATF fluid?
I have already touched on several aspects of the work from above, and now I would like to talk in detail about how it works.
Temperature
The average operating temperature of the liquid is about 80 - 95 degrees Celsius, although at some points, for example, in traffic jams in summer, it can warm up to 150 degrees. But why? It's simple - the machine does not have a hard transmission of torque from the engine to the wheels. Therefore, sometimes the engine gives increased power, which the wheels do not need to overcome road resistance - the excess energy must be absorbed by the oil and spent on friction, hence the heating in traffic jams is simply huge.
Foaming and corrosion
Large masses of oil that move under enormous pressure create a favorable environment for foaming ATF fluid. And in turn, this process leads to the oxidation of the oil itself, and metal parts. Therefore, the fluid must have the right additives to minimize these processes. Moreover, additives are selected each time different, there are no identical ATF oils. This is because the internal structure of automatic transmissions is different everywhere, in some devices there is more metal, in others there is metal - cermet, in others steel - bronze, this must be taken into account.
Liquid resource
As you understand, this liquid is essentially unique, it works in very adverse conditions, but even at such temperatures it can work for many thousands of kilometers. Its resource is approximately 50 - 70,000 kilometers. However, do not forget that it is not eternal, and after 70,000 kilometers its properties are lost, replacement is required.
Evaporation
Not many people know, but ATF oils can volatilize, so some manufacturers install dipsticks (to measure the level) on their machines. The level may drop due to the removal of vapors through the ventilation system of the automatic transmission cavities, in simple words, through the “breather”. Therefore, it is important to monitor the level, this is a kind of mandatory practice.
Why "ATF is so expensive
But really, why can a liter reach a price of 700 - 800 rubles, and a machine often needs about 8 - 10 liters? But as you understood from above, this is the most technologically advanced liquid, and it evolves every year.
It is much more perfect than motor oil, and even more so than ordinary gear oil, hence the prices. However, again, I repeat, it works in an aggressive environment and for a fairly long period of time, 60 - 70,000 kilometers.
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The gears do not run on traditional gear oils. They are filled with special ATF oil. This fluid is a high-index mineral or synthetic based formulation. Such fluids for automatic transmissions allow the operation of systems that control and manage gear changes. Also, through this fluid, torque is transmitted from the engine to the automatic transmission. Additionally, ATF oil lubricates the friction parts and cools them.
How ATF fluids were created
The first automatic transmission was created in 1938. This design was called Hydramatic. It featured a vacuum gearshift system. This unit was created by Pontiac engineers. Even then, the company was part of the General Motors auto concern.
Since before the launch of any innovative development, they preferred to pre-check it and test it in every possible way, the new automatic transmission was installed on Oldsmobile. The tests went well. And now, in 1939, the Hydromatic was installed as an option on the Oldsmobile Custom 8 Cruiser car. This option cost $57.
The role of General Motors in the creation of the first ATF
By the end of the 40s, automatic transmission had become a familiar part of cars. And it is not surprising that the first ATF oil for automatic transmissions was created by General Motors specialists. It was the world's very first specification for a transmission fluid. It was called Type A. The liquid was created in 1949. Then GM began to develop gear oils, and later classify, put forward the most stringent requirements for them. Products that were created in the laboratories of General Motots, due to the lack of competition, have become the international standard for working fluids for any type of automatic transmission.
From to new technologies
In 1957, the already successfully existing specification was revised and decided to add one small new application - Type A Suffix A transmission fluid (abbreviated name ATF-TASA). After 10 years, they created specification B (this is ATF Dexron-B).
As the main ingredient, due to which the liquid had lubricating properties, blubber was used - this is fat that was obtained from whales. But then the development of technology in the production of automatic transmissions forced the concern to introduce something new. So, in 1973, a new Dexron 2C specification is being developed. In 1981, it will be replaced by Dexron-2D. After a flurry of negativity from animal advocates hit the corporation, as well as after a ban on catching whales, the company in 1991 creates the innovative Dexron-2E formula. The difference of this product is that it is created on a synthetic basis. Previously, the lubricant was produced on a mineral basis.
Birth of Dexron-4
In 1994, the entire world community learned about the new specifications, which set out new requirements for viscosity properties and temperature characteristics. Also, the specification implied more improved frictional properties. These are Dextron-3F and Dextron-3G. After 8 years, Dextron-3H comes out. But the most modern and most rigid is ATF Dexron-4. Of course, today there are other specifications from other car manufacturers. These are such giants as Ford, Toyota, Huinday and others.
How is ATF different from other gear oils?
To understand the difference, you need to approach the issue from afar. In cars, oils are used for the engine, gearboxes, hydraulic boosters and ATF oil. What are the similarities between all these liquids? These oils are based on hydrocarbons, which are obtained through the processing of fossils. This gives some similarities in characteristics. All of these products have lubricating properties, increase the slip between rubbing surfaces.
Also, all these fluids have good heat dissipation characteristics. They are similar in texture. This is where all the similarities end. This is sometimes the cause of gross errors when a novice motorist pours oil for “mechanics” into the automatic transmission, and brake fluid into the power steering.
Main properties of ATF
ATF oil is one of the most complex fluids in its composition among all lubricating mixtures used in a modern car. Such lubricants are subject to high requirements and standards. The oil should have a lubricating effect - due to this, friction is reduced, and at the same time, wear in the gearbox elements is reduced. In this case, the friction forces in the friction groups should increase. This will reduce slippage of other nodes.
Also one of the important properties is heat dissipation. The oil has high thermal conductivity and fluidity characteristics. In this case, the liquid should not foam during operation. An important point is stability, namely the absence of oxidative processes when heated to high temperatures at the time of contact with oxygen. Additionally, the oil must also have anti-corrosion properties. This is necessary in order to prevent the formation of corrosion on the internal components of the mechanism. Automatic transmission fluid must be hydrophobic (this is the ability to expel moisture from the surface). In this case, it is necessary that the liquid retains its flow characteristics and hydraulic characteristics. ATF grease has stable characteristics and a high compression ratio over the widest possible temperature range. Another point is a decrease in penetrating ability through automatic transmission and the presence of a dye.
Typical characteristics for automatic transmission lubricants
Consider several ATF oil specifications, characteristics and numbers. For the Dexron-2 specification, the kinematic viscosity is 37.7 at 40 C. At 100 degrees, the same parameter will be 8.1. For Dexron-3, kinematic viscosity is not standardized at all, as well as for other specifications.
The viscosity of ATF oil according to Brooksfield for Dexron-2 at a temperature of 20 degrees should be 2000 mPa, at 30 - 6000 mPa, at 40 - 50,000 mPa. The same parameter for Dexron-3 will be 10 if the pressure is 1500 MPa. Flash point - no lower than 190 degrees for Dexron-2. For Dexron-3 - this parameter is 179 degrees, but not higher than 185.
ATF oil compatibility
Any oil (whether mineral or synthetic) can be mixed without any consequences. Naturally, more modern fluids have improved characteristics and properties. If a modern liquid is added to an ordinary one, this will improve the properties of the filled oil. The older the specification, the lower performance it will have. Also, the shelf life of ATF oil is an order of magnitude lower. Experts recommend changing this fluid every 70 thousand kilometers. It is worth noting that many modern manufacturers do not regulate the replacement period for this fluid. It is filled for the entire service life. But when a car takes care of 200 thousand kilometers on one oil, this is not very good. The fact is that the fluid in the automatic transmission is working. It is she who transmits torque from the engine to the wheels. This oil is constantly in action, even when the car is in neutral speed. Over time, it collects the products of development.
These are metal shavings that clog the filter and sensors. As a result, the box ceases to function normally. Now to the issue of compatibility. No brand will ever fully disclose all information regarding the composition and properties of the fluid produced. Often, manufacturers are limited to only marketing information and advertising that forces you to buy only a specific product. But often this information is not substantiated. For transmissions with hard engagement of torque converter lockups, it is recommended to use fluids with constant frictional characteristics.
For automatic transmissions with GTF blocking, products with variable properties should be poured. And finally, regardless of the automatic transmission model, all parts, bearings, gears and other elements are made from the same materials. This means that different types of ATF are not particularly different from each other.
About application features and compatibility
If the oil in the box changes entirely, then it is best to purchase a more expensive product. In this case, constant or variable frictional characteristics must be taken into account. If the budget is limited, then even ATF universal oil will do. Its use will not affect the quality of the box. If the liquid is added, then experts recommend using products of a class higher or at least not lower than the filled one. But if its resource has reached 70 thousand kilometers, a complete replacement is necessary. Additional flushing is recommended. This operation takes an additional 20 liters of oil. It is not cheap, but judging by the reviews, this operation perfectly washes the chips. And its presence, as you know, complicates the operation of an automatic transmission.
So, we found out what ATF oil is for automatic transmission.
