Atf oil for automatic transmission-characteristics and application and compatibility of oils atf. Complete information about ATF What is atf in automatic transmission

To fully understand this issue, you need to go from afar. Consider what oils are generally used in cars, how they fundamentally differ. Without going into details, these are engine oils, transmission (gear) oils, hydraulic booster oils, ATF and brake fluid. The similarity of all these oils, firstly, is that they are based on hydrocarbons obtained by processing fossil hydrocarbon raw materials, which accordingly gives some similarity in properties. All of them have a lubricating effect that increases slip between rubbing surfaces and a hydrorobic (repelling down) effect, as well as the ability to remove heat. A bit similar in appearance: oily to the touch with similar ones in the first approximation, this is where the similarity in properties ends.

This sometimes gives rise to irreparable errors when, for example, engine oil is poured into an automatic transmission, and brake fluid is poured into a hydraulic booster. Naturally, these actions are immediately followed by a breakdown of the unit. So how does ATF (Automatic Transmission Fluid) globally differ from all other substances poured into car devices.

ATF Properties

The fact is that ATF is the most complex fluid in a car, which requires a number of properties that sometimes contradict each other.

1. Lubricating effect: reduced friction and wear in bearings, bushings, gears, pistons, solenoid valves.
2. Increase (modification) of friction forces in friction groups: reduction of slippage (shift) between clutch pack frictions, brake bands, torque converter blocking.
3. Heat removal: rapid removal of heat from the friction zone due to thermal conductivity and fluidity.
4. Foam suppression: no foaming in air contact areas.
5. Stability: no oxidation when heated to a high temperature and in contact with atmospheric oxygen for the longest possible time.
6. Corrosion resistance: prevention of corrosion formation on the internal parts of the automatic transmission.
7. Hydrophobicity: the ability to expel moisture from serviced surfaces.
8. Fluidity and hydraulic properties: the ability to maintain stable fluidity and hydraulic properties (degree of compression) in a wide temperature range from -50 C to +200 C.

So what should be poured into the automatic transmission and how to top up ATF if the required ATF brand is not at hand or it is generally unknown what is filled in the automatic transmission?

To simplify the answer, we first make a few assertions.

1. Any type of ATF - mineral water, semi-synthetics or pure synthetics are mixed together without any negative consequences. More modern ATFs have better performance and properties.
2. The addition of a more modern type of ATF to a less modern type improves its properties.
3. The less modern ATF, the worse its properties and therefore it must be changed more often, but even the most dense ATF of the DEXTRON II type will work with the most modern automatic transmission of the ZF6HPZ6 type without any problems. Proven in practice!
4. No manufacturer discloses complete information about the composition and properties of the ATF they produce, limiting themselves to general advertising recommendations. The exception is special highly modified oils, in which their manufacturers do not know what they have mixed and promise a fantastic effect. Such liquids, if there is a desire to use them, are best poured without mixing with anything, since the effect is unpredictable.
5. Manufacturers' guidelines for the use of ATF in their products are largely driven by the goal of increasing profits and are not always technically justified.
6. It is desirable (but not necessary) to use ATF with constant frictional properties for automatic transmissions with hard torque converter lock-ups, and ATF with variable functional properties for automatic transmissions with mains lock-up having a controlled slip mode, the rest is not important.
7. All pieces of iron, gears, bearings, clutches, seals, etc. in automatic transmissions they consist of materials of the same properties, regardless of the manufacturer of the automatic transmission, the nuances are not very significant, which means that different ATFs cannot have fundamentally different properties.

Summarizing all of the above, we draw the following conclusion: if you fill or change ATF in an automatic transmission as a whole, it is advisable to use a more modern and apparently more expensive ATF, taking into account only its frictional properties (variable or constant) for your automatic transmission. If the budget is limited, then you can fill in any ATF that is suitable for the price - this will not noticeably affect the operation of the automatic transmission, but the ATF will have to be replaced more often. Manufacturers' recommendations can be ignored at all. When pouring ATF into an existing liquid, if the same brand is not available, it is necessary to use a liquid with a class not lower than the main one, i.e. DEXTRON III. It is possible to add DEXTRON II, but vice versa, it is undesirable, because if you reduce the properties of ATF in the original automatic transmission, it may start to work worse, if you don’t know what is filled in at all and are afraid to do harm, add the most expensive modern ATF type DIV-DVI, again in friction properties.

ATF Composition

Due to the need to obtain such a large number of multidirectional properties, the composition of ATF is extremely complex and is not disclosed in detail by the Manufacturers. In open information, there are only general data on the chemical and molecular composition of the main additives, it is these additives (additives) that ultimately form the set of properties that ATF should have, detailed formulas of substances and their interactions are classified.

The chemical composition of ATF consists of two main parts - this is the base base and the additive package. The base base is the directly carrier fluid that makes up the main volume. According to its type, the base is divided into three main groups: mineral, semi-synthetic and synthetic. A mixture of mineral and synthetic bases is also used, which is sold as synthetic. Mineral bases include paraffinic (paraffinics) and naphthenic oils, their group in the classification systems XHVIYAPI ATIEL (the tehnical association of the european lubricans american petrolen Institute). Semi-synthetic or conditionally synthetic include hydrated (hidroisomerised) mineral base oils, which are considered improved, but relative to the first group, their VHVI classification, one of the Yubase brand names. But the true synthetic base group is the polyalphaolefin HVHVI (PAD) oils. The technology for their production is extremely complex and expensive at the moment, and in most cases commercially available synthetic ATFs consist of part of a synthetic base with the addition of a mineral or conditionally synthetic base component, which you will never be notified on the packaging.

GATF additives

The second part of the chemical composition of ATF is the additive package. Their chemical composition is also classified by manufacturers, and there is information in the public domain about the general chemical composition and percentage of ions of various substances: phosphorus - P +, zinc - Zn +, boron - Bo, barium - Ba, sulfur - S, Nitrogen, Magnesium, and etc.

In fact, these ions are part of polyesters, which in the mixture create additional chemical compounds, enhancing certain properties of additives.

That is why we are always talking about an additive package with certain characteristics.

Consider the ionic composition of the additive package of the most common DEXTRON III / MERCON ATFs. The total amount of additives in DIII in relation to the base oil is 17%, of which in the composition of ionizers:

• Phosphorus - 0.3% AW in 2-ethyl-hexyl-phosphoric acid, improves anti-wear properties in the ZDDP additive.
• Zinc - 0.23% as part of ZDDP zinc diethyl dithiophosphate - antioxidant properties, anti-wear.
• Nitrogen - 0.9% AW additive (Anti-Wear)
• Boron - 0.16% AW additive, enhances cleaning properties by enhancing ZDDP.
• Calcium - 0.05%, in the composition of calcium phenolates - a washing effect, plus a dispersant in the composition of the base additive TBN, anti-corrosion effect.
• Magnesium - 0.05% detergent properties as part of the base additive, acidity reduction, anti-corrosion effect.
• Sulfur - 0.55% AW additive, plus in the composition of friction modifiers (FM), anti-wear properties in the composition of EP.
• Barium - various%, control partial late.
• Siloxane - 0.005% active defoamer.

The following ions are part of additives that have complex formulas, the details of which are classified, some of their names and the general chemical formula:

• ZDP - zinc phosphate, anti-corrosion effect
• ZDDP - - dithio-phosphate, antioxidant, anti-corrosion.
• TCP - tricresyl phosphate, heat resistance enhancement.
• HP - chlorinated paraffin, high temperature resistance.
• MOG - glycerin monoplast
• Stearic acid
• PTFE - Teflon (almost never used in ATF)
• SO - sulfated EP (Extrime Pressure Additive) stabilizes properties under excess pressure.
• ZCO - zinc carboxylate, corrosion inhibitor.
• NA is a group of alkylated benzenes.
• POE - ethers.
• TMP – lineoleic ether polynols
• MODTP

In total, about a hundred such additives have been developed, and one package of additives can include up to 20 complex substances that, when combined, give a cross effect that creates the desired characteristics for ATF.

History of ATF creation

Experiments on the creation of automatic transmissions began in droves in the 20s of the 20th century, but in those days no one seriously thought about changing the properties of the hydraulic fluids used in them. The first big breakthrough came in 1949, when General Motors introduced the world's first serial development of ATF, designated Type A. It was based on petroleum mineral oil, and sperm whale spermaceti was used as the only additive. Sperm oil was secreted from the unfortunate animal by a special gland and accumulated in two bags located in the depressions between the bones in the upper part of the skull. These sacs served as resonators for the whale's ultrasonic signals. After killing and butchering the whale, the spermaceti fat was frozen from the contents of the spermaceti sacs and hydrated, resulting in a substance called Cetin, the chemical formula of which is C15H31COOC16H33, which was used as the main component of the first ATF.

The quality of ATF Type A turned out to be so high that the mixture practically did not require any modifications, based on the fact that at that time the transmissions were low-speed, and the operating temperature did not exceed 70-90 C. Over time, the power and torque increased, and the original Type A ceased to meet the requirements, as it oxidized at higher temperatures and foamed, unable to withstand high speeds.

The next in the development of ATF was the Type A Suffix A fluid created in 1957 with improved performance. For the first time, additives containing substances based on phosphorus, zinc and sulfur began to be used in minimal amounts (about 6.2%), which made it possible to improve the antioxidant and other properties of ATF.

After that, there was nothing new for ten years, and only in 1967 GM took the next step by creating ATF with index B. From that moment on, a classification called DEXTRON was introduced, and the liquid was called DEXTRON B. Its fundamental difference was that that a significant amount (about 9%) of substances based on barium, zinc, phosphorus, sulfur, calcium and boron was introduced into its composition, which can be called an additive package.

Unlimited chemical harvesting of whales brought them to the brink of extinction, and in 1972 the US government was forced to pass the Endangered Species of Animals and Birds Act, completely prohibiting whale hunting. ATF manufacturers have begun to have dark days. For several years it was not possible to find a replacement for spermaceti fat. When using the fluids left at the disposal of manufacturers, the number of automatic transmission failures increased 8 times in the United States, and the matter smelled like a disaster. It wasn't until the mid-1970s that International Lubricants, in collaboration with renowned organic chemist Philippe, developed a liquid synthetic wax ester called LIQUID WAXESTER, patented under the trademark LXE®, which made it possible to improve the required properties of ATF by an average of 50%. The resulting liquids even began to surpass ATF based on spermaceti in a number of characteristics. Based on this technology, in 1975 GM created DEXTRON II index C with an additive content of 10.5%. But it soon became clear that ATF turned out to be quite aggressive and began to cause corrosion of metal surfaces, so a year later DEXTRON II index D was created, which included additional corrosion suppressant additives. The next step in 1990 was DEXTRON II index E, which included viscosity stabilizers at low temperatures and stabilizers at high temperatures. In 1995, DEXTRON III became the crowning achievement of all creations, as part of which all modern requirements were taken into account and a complex package of additives was introduced. So far, GM has created the DEXTRON IV, DEXTRON V, and DEXTRON VI. In parallel with GM, in-house developers led a number of firms, such as Ford, who created a number of their own ATFs, united by the MERCON classification, Toyota's Tyret classification (DTT).

This led to a fair amount of confusion in the classification of oils and understanding their compatibility with each other and with the design of the automatic transmission. Therefore, over time, it was decided to tie all these standards to the GM-DEXTRON classification. Therefore, on most ATF packages of any company, you can see the inscription on the back of the annotation: “Analogue DEXTRON III” or “DIV”, etc.

What is the difference in the properties of ATF from different manufacturers. Determination of compatibility with the automatic transmission design.

I would like to note right away, no matter what worthy experts say, there is no fundamental difference in the properties of the most modern ATFs. If you go into details, then two main factors are taken as the criteria for difference:

1. Interaction of ATF with various types of friction materials.
2. Various characteristics of friction coefficients in the clutch of friction clutches of frictional properties (variable and constant coefficient of friction).

On the first point: There are about a dozen manufacturers of friction materials in the world, such as Borg Warren, Alomatic, Alto and others, each of which develops its own original compositions. The basis is usually a specially treated cellulose fiber (friction cardboard), in which various synthetic resins are added as a binder, and soot, asbestos, various types of ceramics, bronze chips, fiber composites of the type * and carbon fiber. Accordingly, it is believed that the manufacturer of the automatic transmission selects the type of ATF for the friction material used, selecting the optimal value of the shear coefficient between the clutches at full contact in order to minimize heat generation in the clutch packs. However, regardless of the difference in the composition of friction clutches, all developers use the same chain, therefore, high-quality friction clutches from native companies do not differ much in properties, therefore they react similarly to different types of ATF.

On the second point: The engagement parameters of the friction elements of the automatic transmission are determined by the coefficient of friction. Friction, respectively, is of two types:

• sliding friction that occurs when the friction elements come into contact until they are fully engaged;
• static friction, when the clutches come into a state of full engagement and become motionless relative to each other.

In addition to the clutches in the brake and drive elements of the automatic transmission, there is also a torque converter lock-up clutch, which, when switching from a hydrodynamic (due to the compression of fluids between oppositely located blades) mode of transferring the main torque to a hard one (when the lock is fully pressed against the body and the H / TR works as usual clutch on mechanics) gets the same set of friction effects. However, in G / T modern automatic transmissions of 6 or more steps, an intermediate mode has appeared, called controlled slipping of the lock (FLU - Flex Lock Up) for smoother and more comfortable shifting, when the pressure regulator with a high switching frequency applies and turns off the pressure that controls the lock, keeping it on the verge of slipping. Accordingly, all types of ATF are divided into two classes: with constant friction properties (Type F, Type G) and variable friction properties (DEXTRON, MERCON, MOPAR).

ATF with unchanged frictional properties has a fairly linear picture: as the friction clutch is pressed (slip speed decreases), the friction coefficient increases, and at the moment the friction clutches engage, it reaches a maximum. This gives the effect of clearly working out gears with the allocation of minimal correspondence.

Accordingly, there is a sense of switching effect. When using ATF with variable friction properties, at the initial stage of pressing the friction clutch, the coefficient of friction-sliding has a maximum value, but as they are compressed, it decreases somewhat, reaching again a maximum at full contact, but at this value, the static friction coefficient is much lower. This gives the effect of smoother and more comfortable shifting, but the amount of heat generated increases.

Possible consequences: If you fill in ATF with variable properties in an automatic transmission with a hard inclusion of g / t, this can cause an undesirable effect of slipping the lock. In the case of an unworn automatic transmission, the hydrodynamic transmission will maintain torque until it is fully engaged and nothing unpleasant will happen. In a worn or damaged automatic transmission with burnt locks and clutches, excess slip can aggravate the situation and cause fatal destruction. If, however, in an automatic transmission with controlled slippage of the lock, fill in ATF with unchanged frictional properties, this can cause a harder gear shift, but will not bring tragic consequences. From this we can conclude that it is possible to add ATF with modified friction properties to it, and it will work softer, and if there is a feeling that the automatic transmission is slipping a little more than necessary, you can fill in ATF with unchanged friction properties and it will work more clearly.

In conclusion, I can add that much more serious factors than the friction properties of oils that affect the operation of automatic transmissions are temperature conditions, the degree of wear of friction clutch surfaces and other devices and control components, and frost. Before these factors, differences in ATF properties become negligible. It makes sense to take them into account only if there are ideal operating conditions for a new car.

The latest development on the ATF market

A few years ago, the technologists of the petrochemical company AMALIE MOTOR OIL developed a universal synthetic ATF, which has no analogues in the world, has fantastic properties, which equally meets the requirements of all types of automatic transmissions. The fluid was called "Amalie Universal Synthetic Automatic Transmission Fluid", which made a real revolution in the US market, having received certification from all leading car and automatic transmission manufacturers. A new type of fully synthetic base and a state-of-the-art multifunctional additive package provide unsurpassed protection and stable performance when used in any type of automatic and robotic transmissions, hydraulic boosters and other hydraulic systems, regardless of manufacturer. It successfully replaces the entire line of DEXTRON, MERCON, transmission fluids from Chryster, Toyota, Caterpilar and other manufacturers. The fluid is recommended for use in heavily loaded automatic transmissions from manufacturers such as BMV, Audi, Land Rover, Mercedes, Mitsubishi, Toyota and any other vehicles of the American, European and Asian markets. Two years ago, this ATF appeared on the Russian market. For those car owners who have the means and do not spare them for the maintenance of their iron horses, this product is a real solution.

One of the elements of such maintenance is the replacement of fluid in the automatic transmission. And here the dilemma arises: what kind of oil to fill in - original or universal?

Choosing an automatic transmission fluid

Original oils are more expensive, but there is no problem with them: what is indicated in the instruction manual, such automatic transmission fluid fits the car perfectly. And if the car is under warranty, then the choice should not be a question. But if there are no obstacles to filling universal oil, why overpay? It is important not to make a mistake in the brand of liquid.

The selection is carried out based on the recommendations of the manufacturer. The developers of the car took into account the properties of the liquid, which it shows during the operation of the unit. In automotive chemistry, the "transmission" has the most complex composition, which includes friction modifiers, antioxidants, corrosion inhibitors, various additives - temperature, viscosity, antiwear, detergents, etc.

Always follow the instructions for the car when choosing ATF for automatic transmission

The main criterion, perhaps, is the viscosity. Oils are divided into thick, medium viscosity and synthetic (semi-synthetic). What did the manufacturer say in the instruction manual? So we get only this type of automatic transmission fluid.

Another equally important factor is the temperature range of the liquid. Having determined the maximum air temperature in the current period of operation, we determine the minimum temperature for ensuring lubricating properties. And, based on this, we select the class of oil.

Selection of automatic transmission oil by car brand

What kind of oil to fill in automatic transmission KIA and Hyundai?

I am sure that the owners of these cars know that most of them are equipped with reliable and unpretentious boxes from Mitsubishi. At the moment, the company begins to install units of its own production in its cars. Basically, these are business class sedans. Most often, recommendations for the use of fluids are focused on MMC ATF SP, sometimes Toyota.

As an example on Hyundai IX35, I50, Santa Fe where the A6MF/LF automatic transmission is installed, it is recommended to use the original fluid Hyundai ATF SP-IV.

As for the older modifications of the boxes (A4A / B, F4A, A4C), then they fill in there Hyundai ATF SP-III And Diamond ATF SP III. The main thing is to stick to the SP-III standard.

We will not forget about the latest 8-speed gearboxes of the Korean concern. Use SP-IV-RR

What kind of oil to fill in automatic transmission Volkswagen (Skoda, SEAT)?

Volkswagen automatic transmissions use oil G 052 025 (A2), Esso Type LT 71141 (most common). For DSG (wet type) apply G 052 182 A2. For dry type DSG7 (0am, DQ200) G052512A2. Of the analogues for classic automatic transmissions, fluids with Toyota T-IV approval (comes in the original) are used, and for robotic SWAG, Febi, Motul DCTF.

What kind of oil to fill in an Audi automatic transmission?

In the automatic transmission of Audi cars, Esso Type LT 71141 is most often poured. The number of the original oil, depending on the modification of the box G 052 182 A2(S-Tronic) and G 055 005(classic automatic transmission). Robotic gearboxes (7 gears, wet clutch) use G052182A2 oil. For classic 6 and 8 speed (ZF) ZF LIFEGUARD 6 and 8 are used, respectively.

What kind of oil to fill in a Toyota automatic transmission?

A540H and A241H boxes use TYPE T TT. In the 1990s, TYPE T (II modification) appears, it is used for electronically controlled automatic transmissions, as well as FLU. Later, in 96, the fluid changes to TYPE T (III modification) and TYPE T (IV modification). Please note that these types of oils differ from each other, having different working properties. In most cases, the alignment is as follows: Toyota T4 is poured into 4-speed units, and Toyota ATF WS is poured into 6 and 8-speed units.

At the moment, liquid is poured into new cars of the TOYOTA concern Toyota ATF WS.

What oil to fill in a Ford automatic transmission?

Ford automatic transmissions are filled with ATF, which corresponds to the MERCON V type. For example, for Ford Focus 2 - WSS-M2C919-E.

What oil to fill in PowerShift?

Original oil number: 1 490 763 (1L) and 1 490 761 (5L). Substitutes: SWAG 10 93 0018, Ford WSS-M2C-936-A

What kind of oil to fill in a Mercedes automatic transmission?

DEXRON II oil tolerances - 236.1, 236.5, 236.6, 236.7. To DEXRON III - 236.9 . P the latest modifications of the automatic transmission use Fuchs ATF 3353. Number of original oil for automatic transmission 722.9 until 2010 (tolerance 236.14) - A001 989 68 03. Replacements for Shell ATF 134, Mobil ATF 134, Fuchs Titan EG ATF 134.

Cars manufactured after 2010 (automatic transmission 722.9 ). The liquid in the box may be different. Tolerance 236.15 is used. Original oil -A 001 989 77 03, A 001 989 78 03. Substitutes Fuchs TITAN ATF 7134 FE, Shell ATF 134FE, Shell Spirax S6 ATF 134ME

What oil to fill in a BMW automatic transmission?

BMW cars are equipped with automatic transmissions from the manufacturer ZF. For 5-speed automatic transmissions use the original oil Mobil LT 71 141(aka ESSO LT 71 141). For 6-speed ZF is used Shell M1375.4, also in 6-mortar (ZF6HP) oil is used ZF LIFEGUARD 6, and in modern 8-speed ZF LIFEGUARD 8 Green colour. The liquid that is sold in BMW canisters has an additional markup, but in fact the company DOES NOT produce gear oils, but only pours partners' products.

What oil to fill in a Volvo automatic transmission?

For Volvo automatic transmissions, it is recommended to use ATF Volvo T-IV fluid, number 1161540-8 . Analog Mobil ATF JWS 3309. Since 2010, they have been pouring Toyota WS.

What oil to fill in a Peugeot automatic transmission?

On most Peugeot (Citroen) cars, an AL4 (DP0) box is installed. In this case, the best option would be Mobil ATF LT 71141. You can also use Dexron VI, Mercon V. Mobil 3309 tolerance can be used in 6-mortar.

What oil to fill in an Opel automatic transmission?

The recommended ATF for Opel vehicles, depending on the year, is DEXRON III, DEXRON VI, MERCON V. Original Opel oil number 19 40 184 . The 4-speed oil is filled with Toyota Type TIV approval, the 6-speed (6T series) oil with Dexron VI approval.

What oil to fill in a Chevrolet automatic transmission?

As in the case of the Opel brand, Chevrolet uses it as a lubricant for automatic transmissions DEXRON VI, Mercon V. Depending on the year of manufacture, older models use DEXRON III.

What kind of oil to fill in a Mitsubishi automatic transmission?

The Asian market uses the MMC ATF SP fill recommendation. We already wrote above that Hyundai (installs Mitsubishi boxes on their cars) uses its own Genuine specification. In the American market, it is used and referred to as Mopar 7176. For automatic transmissions manufactured in 1992-1995, it is used ATF SP, 1995-1997 is poured ATF SPII, and after SP III. Likewise, liquid J3 used for Mitsubishi 6-speed automatic transmissions. What kind of oil to fill in a HONDA automatic transmission?

Until 1994, Honda automatic transmissions did not differ either in maintenance or in the choice of special fluid. As for most cars with automatic transmission, it was recommended to fill in DEXRON II type fluid. Everything changed after 94, when the concern announced the development of VTEC, which allows to produce high power from a small engine volume. We will not describe all the nuances, we will only say that the Japanese have developed a unit capable of digesting high power, while having a significantly higher operating oil temperature.

A liquid was developed specifically for this. Honda ATF Z1. However, car owners could observe the inscription DEXRON II on the dipstick, which misled them about the recommended transmission. In fact, this only meant that the car owner could use the latter, but only for a short period of time. In 2010, she released an improved version of the liquid - Honda ATF DW-1

Features of the fluid replacement technology in the machine

Units are divided into two types: serviced and unattended. Serviced boxes have necks, probes, that is, everything is provided for replacement. But in some recent models, the manufacturer, considering it optional, does not provide for this.

The condition of the oil in the automatic transmission can be determined by color

The replacement period in serviced automatic transmissions is indicated in the manual. But! Do not forget that Russian operating conditions are equated to severe, so it is worth changing the fluid twice as often. Example: if the manufacturer indicates a replacement period every 60 thousand kilometers, then it is recommended to change it already at 30 thousand. Fluid level in automatic transmission easy to identify with a dipstick.

The second nuance is the replacement in maintenance-free units. Here the volume cannot be determined. Therefore, we change the oil according to the principle: the volume of drained oil must be equal to the filled one. Only all operations must be carried out on “cold” oil, since when heated, the working fluid of an automatic transmission expands and volumes may vary.

How to check the condition of the oil in an automatic transmission Video

Oils for automatic transmissions are subject to much higher requirements for viscosity, anti-friction, anti-wear and antioxidant properties than lubricants used in other units.

Since automatic transmissions include several completely heterogeneous units in terms of speed and load characteristics - a torque converter, a gear gearbox, a complex system of hydraulic automation and control, in connection with this, the list of oil functions in an automatic transmission is quite extensive:

• Lubrication of moving parts
• Torque transmission
• Pressure transmission in the hydraulic part of the automation system
• Cooling of friction units and dissipation of excess heat that occurs during the transmission of torques
• Anticorrosive protection of dissimilar structural materials of automatic transmission
• Rapid release of air
• Resistant to emulsification with water
• Deposit resistance

Dynamic loads in automatic transmissions are usually lower than in conventional transmissions due to the absence of a rigid connection between the transmission and the engine. But the temperature regime is much tougher - the average operating temperature of the oil in the crankcase of an automatic transmission is +80 ° C, 95 ° C, in hot weather, especially in the urban traffic cycle, it can rise to +150 ° C. The design of the automatic gearbox is such that if more power is removed from the engine than is necessary to overcome the resistance to movement (depending on the condition and slope of the roadway, the coefficient of adhesion of wheels with coating, etc.), then this excess is spent on overcoming internal viscous friction in the oil, which leads to the formation of additional heat - as a result, the oil heats up even more.

High speeds of oil in the torque converter and high temperatures cause intense aeration, leading to foaming and saturation with condensation water and oxygen, which can cause the following negative effects:

• Oxidation of the oil itself
• Intensive corrosion of metals (in addition to direct oxidation of metals by active oxygen, and electrochemical corrosion of the resulting pairs of dissimilar metals)
• Decreased efficiency of hydraulic automatics, reduced efficiency when transmitting torque in a torque converter

An important factor is the use of automatic transmission of dissimilar metals in friction pairs, including the use of coatings from precious ones in terms of their compatibility with the applied oil, antiwear and extreme pressure additives. It is also necessary to take into account the fact that in order to ensure high efficiency of the torque converter, we use low-viscosity cSt oil with the main difference from conventional high-viscosity gear oils in kinematic viscosity.

The base oil is a highly refined mineral oil, semi-synthetic or fully synthetic oil, with a very high viscosity index of 140, 200, and a natural high low temperature fluidity.

Additives - antioxidant, anti-corrosion, extreme pressure, anti-wear, thickening, it is possible to introduce a coloring pigment, which in some versions of the liquid plays the role of an indicator of the product's performance in terms of performance properties (although, as a rule, the color of the liquid does not characterize its belonging to a certain class) .

Due to the fact that specific requirements are put forward for transmission and hydraulic fluids for automatic transmissions by manufacturing companies, today there are a number of basic commonly used and private tolerance-specification requirements.

These are the specifications put forward by the companies:

• General Motors Co.
• Caterpillar
• Vickers Mobile Hydraulics
• Mitsubishi
• Toyota
• Nissan
• Honda
• Hyundai
• ZF TE ML

The world's largest automatic transmission company, General Motors Co (General Motors Corporation) has long been developing and putting forward separate specifications for automatic transmission fluids ATF (Automatic Transmition Fluid). A feature is the requirement to reduce the friction coefficient of the fluid as the sliding speed in the hydraulic transmission decreases (the difference in the rotational frequencies of the pressure and turbine wheels in the torque converter).

• ATF type "A", suffix "A" or Dexron I. An early classification by GM, developed in the post-war period in conjunction with the American military armored research center Armor Research, ATF fluids that successfully fulfilled these requirements were assigned qualification numbers AQ (Armour Qualification no). The letter “A” comes from the name of this qualification system
• Dexron B (General Motors 6032 M) - current GM specifications, tolerance data begins with the letter "B"
• Dexron II (General Motors 6137 M) or, what is the same - Dexron II D (General Motors D-22818) - a more stringent set of requirements for fluids, usually mineral-based, for automatic transmissions, in order to protect the environment, prohibiting use of spermaceti oil as an additive
• Dexron IIE (General Motors E-25367) fluid specification, sometimes synthetic based, for GM automatic transmissions manufactured after January 1, 1993. Characterized by higher anti-wear properties, extended service life
• Dexron III latest specification for synthetic (rarely mineral) based automatic transmission fluids, higher thermal and oxidation stability, improved frictional characteristics

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.

Do I need to change the fluid in an automatic transmission?

If you believe the operating instructions, then in the case of a new car, the “automatic” does not require any maintenance up to a mileage of 100 thousand kilometers. True, oiler skeptics frown: they say, by 40-50 thousand it would be nice to fill in fresh ATF (Automatic Transmission Fluid), suitable for a particular machine. But along with specialized fluids, the so-called “cartoons” are also popular - ATF with the beautiful name Multi-Vehicle (“multi-weekle”, that is, for different cars), which can be poured into almost any automatic transmission without bothering to look for a branded oils.

It would seem, why are they needed if you can buy your own liquid? The answer is simple: for the secondary. They are taken by those who are already on the second circle of the odometer riding the "machine" and have no idea what and when it was poured. In addition, not every warehouse or store keeps a bottle in its bins that is obviously suitable for your AT. The supply of liquid under the order can take a long time - and the "cartoons" correspond to many tolerances. So the question here is not at all in the price (“cartoons” are not cheaper), but in the speed of solving the problem.

In general, for the test, we took eight liquids with the designation Multi-Vehicle. Checking the "cartoons" seemed very interesting to us, because from a technical point of view, creating such a product is very difficult. It is clear that it is an impossible task to evaluate their versatility in full: the number of requirements, approvals and specifications for ATF exceeds a hundred (both car manufacturers and gearbox manufacturers are trying). Therefore, we have combined all kinds of criteria into groups that are closer and more understandable to the consumer.

Here are the parameters by which we will check them.

1. Friction losses in the gearbox. I wonder if the driver will feel the difference or not?

2. Influence of fluid on the efficiency of energy transfer from the engine to the transmission. Dynamics and fuel consumption depend on this.

3. Cold start.

4. Protective properties of the liquid. By the rate of wear of friction pairs, we will estimate the proximity of repair or, God forbid, replacement of the box.

HOW WE CHECK

The main physical and chemical indicators - viscosity and viscosity index, flash point and pour point - we measured in a certified laboratory. Friction losses and wear were evaluated on a friction machine - a device that simulates the operating conditions of various friction pairs. The tests were carried out in two stages. At the first stage, a model similar to gearing was investigated. At the second stage, the operating conditions in the bearings were simulated. At the same time, friction coefficients, oil heating, wear of friction pairs were measured. Wear was determined by accurate weighing of parts before and after the test cycle, and for the bearing model - also by the method of holes. This is when, before testing, a hole of a fixed size is cut on the working surface of the sample, in the zone most subject to wear, and at the end of the test, a change in its diameter is recorded. The more it increases, the higher the wear.

Tests for each liquid at one stage and another lasted a long time: one hundred thousand load cycles for the bearing model and fifty thousand for the gear model.

DISTRIBUTION OF gingerbread

So, let's see what happened. It immediately caught my eye that the effect of the brand of liquid on the coefficient of friction was very ambiguous. For the gearing model, all differences were within the limits of the measurement error. The Dutch NGN Universal ATF looks a little better than others. But for the bearing model, everything is different - the run-up of the measured parameter is quite large. Here the best performance is for Motul Multi ATF and Castrol ATF Multivehicle fluids.

How critical is the difference in this parameter? On the scale of the entire power unit (engine and gearbox), the proportion of friction losses in the box is not so large (if we do not take into account losses in the torque converter). On the other hand, oil heating due to friction when operating on different fluids differs much more significantly: the average cumulative difference for the gear and bearing models is approximately 17%. From the point of view of the temperature effect, this difference is very noticeable - up to 10–15 degrees, which give a change in the efficiency of the torque converter by noticeable units of percent. Motul synthetics look better than others here. Only slightly inferior to her liquid NGN Universal and Totachi Multi-Vehicle ATF.

The heating of the liquid also affects its viscosity: the greater the heating, the lower it is. And with a drop in viscosity, the efficiency of the torque converter decreases. Many people remember problems with “automatic machines” of not very young “Frenchmen”, when, due to an increase in the temperature of the liquid (especially in traffic jams in summer), they refused to work at all!

Go ahead. It is very important that the dependence of viscosity on temperature be as flat as possible. One of the main criteria for this flatness is the viscosity index: the higher it is, the better. The leaders here are Mobil Multi-Vehicle ATF, Motul Multi ATF and Formula Shell Multi-Vehicle ATF. The “cartoon” of the NGN brand is not far behind them.

Let's see how the viscosity of the liquid in the working area of ​​the box changes, taking into account its heating. The difference is palpable! For kinematic viscosity, it reaches 26%. And the efficiency of "automatic machines" (especially old designs) is quite small and is largely determined by the efficiency of the torque converter - which just suffers when the viscosity of the working fluid decreases.

The smallest drop in viscosity was found in Motul Multi ATF, Formula Shell Multi-Vehicle and NGN Universal ATF oils. The largest is in Totachi Multi-Vehicle ATF. These are, of course, comparative results; a direct transfer to the efficiency of the box cannot be made. But for forced motors, in which the load on the automatic transmission components is higher, it is preferable to have fluids with a more stable characteristic.

Low-temperature properties were evaluated by a combination of several parameters. Obviously, all liquids, including ATF, thicken in the cold. This means that with a fair minus overboard, excessive viscosity will interfere with cranking the engine at the start, since the clutch pedal is not provided on machines with an automatic machine. Therefore, we determined the kinematic viscosity of each sample at three fixed negative temperatures. In addition, we estimated the temperature at which the kinematic viscosity of the oil reaches a certain fixed value, conditionally taken as the limit, at which the gearbox can still be "turned".

At the same time, the freezing point was determined: this parameter is included in all descriptions of ATF and indirectly indicates on the basis of which base the liquid is made - synthetic or semi-synthetic.

Synthetics with a high viscosity index again won in this nomination: Motul Multi ATF, Mobil Multi-Vehicle ATF, NGN Universal ATF, Formula Shell Multi-Vehicle. They also have the lowest pour points. And finally, the protective functions of fluids, that is, their ability to prevent wear. We studied the wear of two models - gearing and plain bearing, since in a real box the operating conditions of these units differ markedly. Consequently, the properties of ATF, which reduce wear, must be different and linked to the operation of the torque converter. And here we found a scatter in the results. The leader in minimizing gear wear is Mobil Multi-Vehicle ATF, while Motul Multi ATF and Totachi Multi-Vehicle ATF won the plain bearing competition by a wide margin.

TOTAL

If during traditional examinations of gasoline and motor oils, as a rule, we revealed only minor differences between one sample and another, here the situation is different. In terms of key parameters, different ATFs have a significant run-up. And given that the degree of influence of this difficult liquid on power, fuel consumption, and the resource of the box is very noticeable, then you should think about its choice. Good synthetics with a high viscosity index are the best choice, which will protect your nerves during a winter start in a fair frost, and will not create problems after a long standing in a traffic jam under the hot sun.

Let's leave the degree of compliance of Multi with its name on the conscience of their developers. At the very beginning, we noted that it was unrealistic to check in practice each ATF in all the "machines" listed on their labels. By the way, in the descriptions (with a few exceptions), tolerances are either directly or by default indicated by the word meets, that is, “corresponds”. This means that the properties of the liquid are guaranteed by its manufacturer, but there is no confirmation of compliance by the manufacturer of the car or box. In conclusion, we would like to inform you that if the planned life of a new car does not exceed 50–70 thousand kilometers (then a replacement is planned), then you read the article in vain - you will not have to change the “liquid clutch”. And in other cases, the information we obtained should come in handy. Adding up the results from all tests, we found that Motul and Mobil were the best products, with Formula Shell slightly behind.

Our comments to each preparation are in the captions to the photographs.

WHAT SHOULD THE ATF BE?

There is no more complex and controversial device in the transmission of a car than an automatic transmission. It combines two units - a torque converter, which ensures the continuity of the energy flow from the engine to the wheels, and a planetary gear change mechanism.

The torque converter is, in fact, two coaxial wheels: pumping and turbine. There is no direct contact between them: the connection is carried out by a fluid flow. The efficiency of this device will depend on the mass of parameters - the design of the wheels, the gaps between them, leaks ... And, of course, on the properties of the fluid located between the wheels. It acts as a kind of liquid clutch.

What should be its viscosity? Too much will increase friction losses in the box - a fair share of power will be eaten, fuel consumption will increase. In addition, the car will become noticeably dull in the cold. Too low viscosity will drastically reduce the efficiency of energy transfer in the torque converter, increase leakage, which will also reduce the efficiency of the unit. In addition, the viscosity of the liquid in the cold increases greatly, and decreases with increasing temperature - the difference can be two orders of magnitude! And the liquid can foam and contribute to corrosion of the box parts. It is desirable that the liquid retains its properties for a long time: then you can not look into the box for years.

That's not all. The same fluid must work in the torque converter, and in the planetary mechanism, and in the bearings of the box, although the tasks and working conditions in these mechanisms differ sharply. In gearing, it is necessary to prevent scuffing and wear, effectively lubricate the bearings and at the same time not interfere with their work with their excessive viscosity: after all, with an increase in viscosity, friction losses increase. But the efficiency of the torque converter also increases with more viscous fluids.

How many options! Therefore, a complex compromise of properties is required that the ATF fluid must combine.

ATF - LIQUID OR OIL?

The classification refers ATF to gear oils, but its purpose is much wider. After all, lubrication of transmission elements - gears and bearings - is not the only (albeit important) function here. The main thing is that ATF acts as the working fluid of the torque converter. It is she who transfers the power flow from the engine to the transmission, because the properties of this fluid are very important for the efficiency of the automatic transmission.

In the passports for ATF, its viscosity indicators are normalized (at operating temperatures and at negative temperatures), as well as the flash and pour points, and the ability to form foam during operation. After all, it is the viscosity that provides lubrication and, therefore, the performance of gears and bearings, the efficiency of torque transmission from the engine to the transmission.

WHAT ARE THE PROBLEMS?

ATF fluids are very capricious. Not always a modern ATF can fit an old machine of the same brand. The same applies to interchangeability: for example, an “automatic machine” from a “Japanese” in 2006 on a specialized ATF addressed to a modern “German” may become bad ... Such an ateefka will lubricate gears and bearings, but the torque converter may be offended and go on strike. Therefore, each automatic transmission manufacturer is looking for its own solution to the problem. And the more difficult it is to make a universal “cartoon” suitable for everyone.