WhyATFoil is so important in automatic transmission
ATF - Automatic Transmission Fluid, oil (liquid) for automatic transmissions, in automatic transmission performs several functions at once, the main of which are:
- Lubrication
- Transfer of force
- Parts cooling
Reduced wear
The coefficient of friction, which provides fluid in friction clutches, is very important. If the coefficient is too small, then the box will slip, if it is too large, it will work in jerks and wear out quickly.
Life timeATFoil in automatic transmission
Automatic transmission oil - ATF (Automatik Transmission Fluid) has its own service life, after its expiration, the properties of the fluid change and the entire automatic transmission stops working as expected. During the service life, contaminants accumulate in the box, which are wear products of gears and clutches, and oxidation products of the liquid itself.
In most automatic transmissions, the oil filter in the sump serves only as a safety feature and is so coarse that it will only retain chips generated during emergency operation of the box. Therefore, contaminants can both circulate with the liquid and form sediments and sludge in the torque converter, in the sump, and contaminants enter the channels and solenoids, which leads to clogging and box failure. Therefore, the fluid in the automatic transmission must be changed periodically.
Some manufacturers, for example, Mercedes Benz, tried to produce automatic transmissions with a “lifetime” filling, but after the accumulated negative experience, this practice had to be abandoned.
Now, almost all manufacturers recommend changing the fluid at a certain frequency, which is influenced by the operating conditions of the car. If we summarize the recommendations by timing, then on average it turns out that ATF must be replaced at least once every 60 thousand kilometers, but this period may differ for each automaker.
If you operate the car in city mode, it is recommended to change the ATF oil in the automatic transmission every 40 thousand kilometers.
Full or partial replacementATF oils (fluids) in automatic transmission
In the general case, the replacement procedure looks like draining some of the fluid through the plug in the sump and replenishing it with fresh through the hole in the dipstick. Now, with the complication of box designs and the release of units without a probe, the procedure for such a replacement has become somewhat more complicated, but has not fundamentally changed.
There are two types of oil changes in automatic transmissions:
- Complete replacement of ATF oil in automatic transmission
- Partial oil change in automatic transmission
Let's assume that the middle box contains 10 liters of ATF. With the standard replacement procedure, a maximum of half the capacity will merge from the box - five liters, the rest will still splash in the channels and in the "donut" of the torque converter. When draining, the oil will, of course, take some of the wear products with it, but most of the contaminants will remain inside the automatic transmission. Such a replacement is called partial and is practiced everywhere.
Unfortunately, motorists usually produce partial replacement of the fluid in the automatic transmission.
Reasons for the popularity of partial replacementATF fluid in automatic transmission:
- saving money. And, first of all, this does not apply to the cost of the procedure, which is cheaper than a complete oil change in an automatic transmission, but to the additional costs of ATF oil, which is necessary to completely flush out the waste from the gearbox system.
- Physical accessibility. A partial oil change in an automatic transmission is carried out in almost any service. A complete oil change requires special equipment.
Disadvantages of partial oil change in automatic transmission:
- About half of the contamination of the automatic transmission remains inside.
About half of the oil remains in the system, partially losing its properties.
Complete replacement of ATF oil in automatic transmission
A complete replacement is a much rarer procedure, but its effectiveness is not comparable to a partial replacement. A complete replacement is carried out using special equipment that allows the use of special compounds for flushing automatic transmissions.
Pictured: a Gear Tronic engine washer using a dedicated automatic transmission flush.
Benefits of full replacementATF oils in automatic transmission:
- Full oil update in automatic transmission
- Washing out all contaminants and processed products from the automatic transmission
- Extending the service life of the automatic transmission
As statistics show, the additional costs of a complete replacement of ATF oil in automatic transmissions pay off many times over by extending the life of the automatic transmission.
The procedure for a complete automatic transmission fluid change is very popular in Russia in the Far East and Siberia, where the difficult operating conditions of passenger vehicles justify the additional costs. In the Central regions of Russia, car owners know quite a bit about this technology so far.
The importance of choosing oil for replacement in automatic transmission
When changing the oil in an automatic transmission, we recommend that you take the choice of ATF fluid with all responsibility. For example, LIQUI MOLY produces oils that not only fully meet the requirements manufacturers of automatic transmissions, but also lays an additional resource of work in all main parameters.
How to choose the optimal and best oil for your gearbox.
Oil should be selected in accordance with the tolerances specified in the technical documentation for the car. If you do not have the opportunity to use the manual for any reason, then you can easily select the required ATF fluid in the selection catalog
AND . These are the most popular fluids that have basic approvals and specifications from car manufacturers and automatic transmission units.
– suitable for almost all CVT variators.
Until recently, it was believed that the resource of an automatic transmission rarely exceeds 200 thousand kilometers, but a regular, once every 60 thousand km, ATF oil change with flushing can at least double it.
For proper and timely maintenance, the car will answer with an increase in its service life.
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We present a revised version of our material on the interchangeability of different types of ATF. It takes into account the changes in the world of transmissions and oils in recent years, changes in logistics and prosperity ... Let's start with a direct answer to the question in the title, and then go through the main Toyota transmission fluids. Working fluid specification for domestic market models from the 1980s (A13#, A24#, A54#, A4#, A34#, A44# series machines, etc.). In foreign markets, these models were ordered to be filled with Dexron II/III type ATF without mentioning D-II. There is no technical sense in acquiring this particular liquid. Any ATF meeting Dexron II/III specifications should be used. This Toyota liquid is not in the repair or operating manuals, since it appeared much later than the end of the production of models with classic automatic machines. Supplied in all markets as an original replacement for the obsolete ATF D-II. There is no technical sense in purchasing this particular liquid, but under specific conditions, D-III may be more affordable and cost-effective than branded ATFs. Used from 1988 to 2002 in "all-wheel drive" automatic transmissions A241H and A540H for better operation of the partial locking center differential clutch. The original is still supplied to the domestic market. In the foreign market, Type T-IV is semi-officially considered a replacement for Type T, however, the T-IV canister directly states - "not recommended for use in machines for Dexron 2/3 or Type T". Many years of local practice has shown that cars with these automatics work perfectly on conventional Dexron type ATFs without any deterioration in the functioning of the four-wheel drive. The offer on the market for Type T is small, and there is no point in purposeful acquisition. Use as a replacement for Type T-IV can damage fairly old transmissions, so it is best to use less aggressive Dexron II or III specification fluids. ATF Type T II ATF Type T III Basic specification for all Aisin boxes after 1997 (U44#, U34#, U24#, U14#, early U15#, A65#, late A24#E, A34#). At the very beginning of the 2000s, traditional ATFs such as Dexron III were successfully used instead of the then rare and expensive T-IV. Later, independent oil manufacturers launched the production of ATF specification 3309 and universal ATF, and later the offer of the original T-IV grew so much that it became perhaps the most affordable liquid of its specification - it is often purchased by owners of other car brands with similar Aisin (Audi, Chevrolet, Daewoo, Fiat, Ford, Mazda, Opel, Porsche, PSA, Renault, Saab, Suzuki, VW, Volvo etc). Using the Dexron specification instead of T-IV ATF does not entail negative consequences, but today it is no longer practical. Valid since 2004, the main specification used in modern 5/6/8-speed automatics (series U15#, U66#, U76#, A75#, A76#, A96#, AA8#, AB6#). Differs in significantly lower viscosity in comparison with the previous ATF T-IV. Liquid in sufficient quantity is presented on the market. It is equally valid to use either the original WS or any ATF conforming to the JWS 3324 specification, depending on the specific circumstances. Together with the first Toyota CVTs in 2000, a specialized working fluid for CVTs appeared. It is optimal to use the original CVTF TC, which is presented in sufficient quantities on the market. Any fluid that meets the JWS 3320 specification can be used. General purpose CVTFs can be used if the need arises. Since 2012, a gradual transition of all CVTs to the new "energy-saving" FE fluid has begun - with a noticeably lower viscosity and fewer useful additives. It is optimal to use the original CVTF FE, which is presented in sufficient quantities on the market. In case of urgent need, it is possible to use universal CVTF. "Why write about it? Today everyone can afford the original"
"Oil or ATF - scholasticism?"
"Why are GM and Dexron taken as a starting point?"
A bit of spec history from GM:
Used in 1990-1997. for some automatic machines with electronic control (A34# series on classic sedans). Officially replaced by T-IV.
In practice, it has been successfully replaced by any traditional ATF. Today, the use of Type T-IV as a substitute can damage fairly old boxes, so it is best to use less aggressive fluids according to the Dexron II or III specification.
Used in 1994-1998. on some machines with Flex-LockUp (part A34#, A35#, A541E, A245E). Officially replaced by T-IV.
It is equally correct to use both the original Type T-IV fluid and any ATF that meets the JWS 3309 specification - depending on the specific circumstances.
Let now there are no problems either with the availability or with the price of the original working fluids. But the question is different - perfectly reasonable advice "Must use recommended fluids" too often replaced by the slogan "You can not use anything other than the original!" It is impossible to put up with this rough manipulation, once thrown by cunning dealers in Japanese spare parts, picked up by officials and smashed by a mass of owners far from technology.
In manual transmissions, the transmission oil almost exclusively serves as a lubricant. In an automatic transmission, the main task liquids- power transmission from the engine to the box, then work in the hydraulic control system, providing the necessary friction in the clutches, cooling the rubbing elements and lubrication itself. Therefore, the broader concept of ATF (Automatic Transmission Fluid) has been established - automatic transmission fluid.
Today, the GM-Ford joint venture for the production of automatic transmissions is on the sidelines of life and deep in the shadow of the world's transmission giants - Aisin, ZF, HPT, Jatco ... Nevertheless, it was GM who were the founders of the mass use of automatic transmissions, the world's largest OEM suppliers of automatic transmissions, and their fluid specification for many years became synonymous with the very concept of ATF.1949
ATF Type A - GM's first ATF specification
1957
ATF Type A suffix A - specification update
1967
Dexron B - the first specification with the Dexron designation proper
1972
Dexron IIC - variant with new friction modifiers
1975
Dexron IID - a revised version of IIC that has become the most common standard and synonymous with ATF for many years
1991
Dexron IIE - improved specification with better viscosity-temperature properties
1993
Dexron IIIF - unified replacement for IID and IIE
1997
Dexron IIIG - new requirements for frictional and antioxidant properties with IIE viscosity characteristics
2003
Dexron IIIH - advanced base with better durability, protection against oxidation and foaming
2005
Dexron VI - a new, noticeably less viscous fluid
- Specifications "Dexron IV" and "Dexron V" officially did not exist, although in slang it could be called IIIG and IIIH. The marketing designation "D-IV" for late dexrons was sometimes used by independent oil producers on the market.
- Shortly after the release of the D-VI, GM canceled all previous specifications and declared the new ATF to be fully backward compatible with all early Dexron types. In reality, the transfer of old boxes to a liquid of a different composition and with noticeably different viscosity characteristics looks extremely doubtful.
- The original GM Dexron VI was notorious for its tendency to darken very quickly (to the point of engine exhaustion), although the manufacturer officially considers this behavior to be the norm.
"Universal Fluids?"
Here is a clear example of how the manufacturer of "Toyota" transmissions - Aisin - refers to the idea of a narrow specialization of fluids: AFW + - an alternative everyone ATF from D-II to WS (as well as a lot of original ATFs from other brands), CFEx is an alternative to all CVTFs, including TC and FE.
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Today it is becoming a trend: one liquid - for all automatic machines, another liquid - for all CVTs, absolute backward compatibility with early ATFs.
Of course, we strongly welcome such official confirmation of our words more than a decade ago about the interchangeability of ATF. But let's try not to forget one more important principle - "do not interfere with the car to work" - for properly functioning boxes of 10-15-25 years of age, it is best to continue to use the fluid that they have been driving so far.
"Periodicity?"
It would be appropriate to recall not only "what", but also "when" to pour into the automatic transmission. However, since the beginning of the mass operation of machines, the answer has not changed: every 30-40 t.km it is worth at least a partial replacement (updating) of the liquid, every 80-120 t.km - a replacement with the removal and cleaning of the pan, magnets, mandatory filter replacement. It’s even better not just to “renew” the liquid, but to change it by displacement (with a stand cooler connected through the hoses, through which, when the engine is running, fresh liquid is supplied and the old one is drained - this is how the box lines and the torque converter housing are washed).
In the 2000s, many new machines lost control probes, and the frequency of mandatory ATF replacement disappeared from the instructions (but the concept of "working fluid is designed for the entire service life" arose). Officially, it is proposed to check the condition of the fluid every 40 t.km, and change it after 80 t.km only under especially difficult operating conditions. Literally following such recommendations will sentence the machine, especially a modern one, already in the second hundred thousand kilometers, therefore, for long and trouble-free operation, it is better to adhere to the traditional ATF replacement frequency, even on the newest cars.
"What did the manufacturer recommend to fill in my box (A541E, A340H, A245E)?"
The exact recommendations of the manufacturer can be called, knowing not only the model of the box, but also the model and year of manufacture of a particular car. Firstly, the same Toyota designations were worn by several assault rifles of slightly different designs. Secondly, the recommendations changed periodically even during the release of one generation of the model (this happened especially often during the appearance of the next, new at that time specifications - T-IV, WS, FE).
"What is flex lock-up?"
Starting in the mid-1990s, Aisin automatic transmissions introduced a "partial lock-up" (FLU - Flex Lock Up) torque converter operation mode. Previously, automatic torque converters operated in two modes - either with torque transmission from the engine only through liquid, or in full lock mode, when the crankshaft, transformer housing and box input shaft are tightly connected by a friction clutch and the torque is transmitted purely mechanically like a traditional clutch. In a box with partial blocking, there is an intermediate mode in which the clutch can slip to one degree or another during the transmission of force. At first, partial blocking was used at light loads and in a rather narrow speed range, but in order to increase efficiency and improve dynamics, full and partial blocking modes on more modern machines began to be used more and more often.
Of course, FLU is not a Japanese know-how, so since the development of the Dexron III specification, the requirements for automatic machines with partial blocking have been taken into account.
"They say if you fill in Dexron instead of T-IV, then there will be shocks?"
When filling any fresh liquid, even the original one, some changes in the behavior of the machine are possible, and not always positive. Fresh ATF always differs from the old one in its chemical / physical properties (even more than two different types of fresh fluid differ from each other), and in its own way affects the operation of the box, which has already "adapted" to the old ATF.
In our practice, no differences in the behavior of serviceable machines when using other ATFs instead of T-IV (even without approval 3309) were noted.
"Where can I find out the viscosity of the original fluid?"
Safety data sheets for all original materials, from paints and oils to antifreezes and fragrances, have been on the main Toyota website for a long time and are regularly updated.
"What is the code for the most correct original Type T-IV?"
The original Toyota ATF can take a variety of external forms: a metal "Japanese" can (black, white, gray), a black plastic "US" bottle, a gray plastic "European" canister ... you should not try to isolate the "more real" from them.
And that's why the retail price of the original ATF in the Russian Federation sometimes turns out to be one and a half to two times lower than in Japan or the USA ... it's better if it remains a little trade secret.
"Type T can be officially replaced by Type T-IV"
On the one hand, in June "98 Toyota issued service bulletin TC003-98 for the American market, according to which the then-new ATF Type T-IV completely replaced the previous T-II and T-III, but did not replace the Type T itself.
On the other hand, in the technical documentation for the domestic market, substitutes for Type T have never been provided, and on the original metal cans with Type T-IV it is still indicated in Japanese and in English "not recommended to use... instead of Type T".
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Which option is more correct? The first and last of the models with a Type T transmission that was distributed on the foreign market was the RAV4 SXA10 (for which these bulletins appeared), however, almost two dozen models were produced in Japan in 1988-2002, moreover, much more massive, with boxes A241H and A540H. Therefore, in matters of operation of all-wheel drive, the practices of the domestic market deserve more trust. And today you can add - if the Japanese Toyota officially recognized the Type T replacement, it would not have traded this fluid in the late 2010s, but immediately sent it into oblivion as T-II, T-III and dozens of other oils of really outdated specifications.
"And in fact, did anyone fill in non-original liquid?"
I would like to remind you that Japanese cars appeared in the country back in those days when there were no mobile phones, the Internet, and in Primorye they drove along the winter road ... And, of course, there was not even the very concept of "original liquids", the commodity import of which only began at the turn of the 2000s. But from the very beginning of the 1990s, tens of thousands of Toyotas (including those with A241H, A540H, A245E, A340E boxes) have been operated here on any available ATF - without breakdowns or problems, and many of them still feel good today.
But before buying a completely non-branded ATF, we strongly recommend that you familiarize yourself with the final part of our articles on the choice of engine oil.
"Everything is clear... but maybe the original is still better?"
Of course, because in addition to the benefits for the car, the use of original working fluids has a calming effect on the owner and increases his heart rate. And do not forget that in addition to the original ATF, the instructions prescribe to use:
only Toyota approved engine oil
only original coolant "Toyota genuine Super Long Life Coolant"
only original power steering fluid "Toyota genuine Power Steering Fluid"
only original brake fluid "Toyota genuine Brake Fluid 2500H"
only original compressor oil "ND-Oil8-11"...
As well as only genuine Toyota parts.
Purchased only from authorized Toyota dealers.
Otherwise, the car will immediately fall apart, right?
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 transmission 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.
Here it is ATF oil, I think you liked the article. Read our AUTOBLOG, subscribe to updates.
Dedicated to the best transmission oils, in English - transmission fluids (transmission fluids). This review only considers oils for automatic transmissions - ATF ( Automatic Transmission Fluid).
Many parameters were taken into account when compiling this top 10, in particular, coefficients of friction, performance, viscosity, reliability, price and customer reviews.
In order to navigate among the many oils for automatic transmissions, it will be useful to familiarize yourself with the most popular samples. This is also true when the car is under warranty, and when the vehicle already has high mileage. Interestingly, in 2013, completely different oils participated in a similar rating. You can see the leaders of 2013.
1
place. . It is best for Honda owners to fill in the transmission oil of the same name. The absolute advantage of the original Honda ATF fluids is that the owner of any Honda is guaranteed optimal compatibility with his car. The oil has a minimum oxidation index, allowing you to significantly increase the intervals between replacements. The components it contains also protect O-rings and seals.
2
place. considered one of the best synthetic automatic transmission oils, providing excellent thermal stability. Red Line 30504 D4 ATF oil has a low viscosity level, which favorably affects the performance of the gearbox mechanism at the time of gear shifting.
3
place. High performance gear oil. It forms a high-strength film on the internal parts of the box, which reduces heat loss and reduces wear. Royal Purple is fully compatible with most other automatic transmission oils.
4
place. characterized by compatibility with other Dexron fluids used in automatic transmissions. Experts recommend using ACDelco 10-9030 for cars with high mileage. This oil provides stable viscosity and is not subject to foaming.
5
place. - an oil that helps improve the efficiency of the transmission and (according to the manufacturer) contributes to fuel economy. With Synthetic ATF from Mobil, you can be sure of the durability of the automatic transmission, including in very low temperatures.
6
place. Among the leaders of ATF oils manufactured under the brand name of well-known automakers is and. This synthetic-based oil with the addition of special additives improves shifting performance, regardless of the ambient temperature. The fluid provides optimal lubrication, extending the life of bearings and synchronizers.
7
place. is an excellent choice for owners of machines boxed with both Dexron 2 and Dexron 3 and also meets MERCON requirements. Oil from Castrol well reduces friction between smooth surfaces.
8
place. designed primarily for use in motors of GM concern models. The oil is resistant to oxidation and breakdown processes at high operating temperatures, guaranteeing the stability of properties in extreme vehicle operating conditions.
Automatic transmission oils (ATFs), along with brake fluids and power steering fluids, are the most specific automotive chemicals. If engine oil is drained from the engine, it will start and even work for some time, and if the working fluid is removed from the automatic transmission (AKP), it will instantly become an unusable set of complex mechanisms. ATF is subject to higher requirements for viscosity, anti-friction, antioxidant, anti-wear and anti-foam properties than for petroleum products for other units.
Since automatic transmissions involve several completely different components - a torque converter, a gear box, a complex control system - the range of functions of the oil is very wide: it lubricates, cools, protects against corrosion and wear, transmits torque and provides frictional grip. The average oil temperature in the crankcase of an automatic transmission is 80-90 0 С, and in hot weather during the urban traffic cycle it can rise to 150 0 С.
The design of the automatic transmission is such that if more power is removed from the engine than is necessary to overcome road resistance, then its excess is spent on the internal friction of the oil, which heats up even more. The high speeds of the oil in the torque converter and the temperature cause intense aeration leading to foaming, which creates favorable conditions for oil oxidation and metal corrosion. A variety of materials in friction pairs (steel, bronze, cermets, friction linings, elastomers) makes it difficult to select antifriction additives, and also creates electrochemical pairs in which corrosion wear is activated in the presence of oxygen and water.
Under such conditions, the oil must not only retain its performance properties, but also, as a torque-transmitting medium, ensure a high transmission efficiency.
Main Specifications
Historically, the "trendsetter" in the field of standards for oils for automatic transmissions are the corporations "General Motors" (GM) and "Ford" (Table 1). European manufacturers, both automotive and gear oils, do not have their own specifications and are guided by lists of oils approved by them for use. Japanese automobile concerns do the same. Initially, conventional motor oils were used in the "automatic machines", which had to be changed frequently. At the same time, the quality of gear shifting was extremely low.
In 1949, General Motors developed a special automatic transmission fluid - ATF-A, which was used in all automatic transmissions produced in the world. In 1957, the specification was revised and named Type A Suffix A (ATF TASA). One of the components in the production of these liquids was an animal product obtained from the processing of whales. Due to the increased consumption of oils and the prohibition of whaling, ATFs were developed entirely on a mineral basis, and later also on a synthetic basis.
At the end of 1967, General Motors introduced a new Dexron B specification, later Dexron II, Dexron III and Dexron IV. The Dexron III and Dexron IV specifications were created to meet the requirements for oils for an electronically controlled autotransformer clutch. General Motors Corporation also developed and implemented the Allison C-4 specification (Allison is a division of General Motors for the production of transmissions), which defines the requirements for oils operating in severe operating conditions in trucks and off-road vehicles. For a long time, Ford did not have its own ATF- specifications, and Ford engineers used the ATF-A standard. Only in 1959 did the company develop and implement the M2C33-A / B proprietary standard. Fluids of the ESW-M2C33-F (ATF-F) standard are most widely used.
In 1961, Ford issued the M2C33-D specification, taking into account new frictional requirements, and in the 80s, the Mercon specification. Oils that meet the Mercon specification are as close as possible to Dexron II, III oils and are compatible with them. The main differences between the specifications of General Motors and Ford are different requirements for the frictional characteristics of oils (for General Motors, the smoothness of gear shifting is in the first place, for Ford, the speed of gear shifting). Typical characteristics of oils for automatic transmissions are given in Table. 2.
Tab. 1. Development of oil specifications
| General Motors Company | Ford company | ||
| Year of introduction | Specification name | Year of introduction | Specification name |
| 1949 | Type A | 1959 | M2C33-B |
| 1957 | Type A Suffix A (ATF TASA) | 1961 | M2C33-D |
| 1967 | Dexron B | 1967 | M2C33-F (Type-F) |
| 1973 | Dexron II C | 1972 | SQM-2C9007A, M2C33-G (Type-G) |
| 1981 | Dexron II D | 1975 | SQM-2C9010A, M2C33-G (Type-CJ) |
| 1991 | Dexron II E | 1987 | EAPM-2C166-H (Type-H) |
| 1994 | Dexron II | 1987 | Mercon (added in 1993) |
| 1999 | Dexron IV | 1998 | Mercon V |
Oils of obsolete specifications are still used in many European cars, and very often as oils for manual transmissions.
In automatic transmissions, most modern car manufacturers recommend oils that meet the requirements of Dexron II, III and Mercon (Ford Mercon) specifications, which, as a rule, are interchangeable and compatible. Oils that meet the latest specifications, such as Dexron III, can be used to top up or replace in mechanisms that previously used oils that meet the Dexron II specification, and in some cases ATF - A. Reverse replacement of oils is not allowed.
Tab. 2. Typical characteristics of oils for automatic transmissions
| Properties | Dexron II | Dexron III | Allison C-4 | Mercon |
| Kinematic viscosity, mm2/s, not less than at 40 0C | 37,7 | Not standardized, definition required | ||
| at 100 0С | 8,1 | 6,8 | ||
| Brookfield viscosity, mPa s, max, at temperature: - 10 0C |
800 | - | Specify the temperature at which the viscosity of the oil is 3500 cP | - |
| - 20 0C | 2000 | 1500 | 1500 | |
| - 30 0C | 6000 | 5000 | - | |
| - 40 0С | 50000 | 20000 | 20000 | |
| Flash point, 0C, not below | 190 | 179 | 160 | 177 |
| Ignition temperature, 0С, not higher | 190 | 185 | 175 | - |
| Foam test | 1. No foam at 95°C | 1. No foam at 95°C | ASTM D892 Stage 1 - 100/0 MP | |
| 2. 5mm at 135 0C | 2. 10mm at 135 0C | Stage 2 - 100/0 ml | ||
| 3. Destruction within 15s at 135°C | 3. Destruction within 23s at 135°C | Stage 3 - 100/0 ml Stage 4 - 100/0 ml | ||
| Corrosion of a copper plate points, no more | 1 | 1 | No blackening with flaking | 1 |
| Rust protection | No visible rust on test surfaces | No traces of rust or corrosion on control plates | No visible rust | |
| Wear tests according to ASTM D 2882 (80 0C, 6.9 MPa): weight loss, mg, max | 15 | 15 | - | 10 |
On the Russian market, the range of oils for automatic transmissions is quite large and, with rare exceptions, is represented by imported oils (Table 3).
Tab. 3. Oils for automatic transmissions
| Chevron Supreme ATF (USA) |
Multipurpose automatic transmission fluid. Recommended for FORD cars produced after 1977, General Motors cars and most other foreign cars. Also recommended for hydraulic boosters and hydraulic systems. Dexron III and Mercon. |
| Аutran DX III (VR England) |
Semi-synthetic universal gear oil for automatic transmissions. Meets specification requirements GM Dexron III, Ford-Mercon, Allison C-4, rd mM3C. Special approvals: ZF TE-ML 14. |
| Аutran MBX (VR England) |
Semi-synthetic gear oil for automatic transmissions and power steering. Meets specification requirements GM Dexron III, Ford Mercon, Allison C-4. Special approvals: MB236.6, ZF TE-ML 11.14, MAN 339 Tupe C, Renk, Voith, Mediamat. |
| Ravenol ATF (Germany) |
All-weather gear oil for automatic transmissions and transmission units of cars and trucks. Special approvals: MB 236.2; Busgetriebe Doromat 973, 974; MAN 339A. |
| Ravenol Dexron II D (Germany) |
Meets specification requirements GM Dexron II, Allison C-4. Special approvals: MAN 339 Tup C, MB 236.7. |
| Ravenol Dexron F III (Germany) |
All-weather universal gear oil for automatic transmissions and transmission units of cars and trucks. Meets specification requirements GM Dexron III, Allison C-4, Ford Mercon. Special approvals: MB 236.1, 236.5; ZF TE-ML-03,11,14. |
All oils, as a rule, have been tested for compliance with the specified specifications and have special approvals from equipment manufacturers.
Although the performance level of ATF is determined by the specifications of the automotive manufacturers, a significant proportion of the oils produced are used in applications other than agro-industrial complex, for example:
- In power transmissions of off-road construction, agricultural and mining equipment;
- In hydraulic systems of cars, industrial equipment, mobile equipment and ships;
- In steering;
- In rotary screw compressors
The composition of oils for automatic transmissions usually includes antioxidants, foam inhibitors, anti-wear additives, friction modifiers and seal swelling. In order to identify and detect leaks as soon as possible, oils for automatic transmissions are dyed red.
