ATF - oil for automatic transmission. Characteristics, application, shelf life. ATF Compatibility

Automatic transmissions do not work ontraditional gear oils. They are filled with a special ATF-oil. This fluid is a high-index mineral or synthetic composition. Such fluids for automatic gearboxes allow for the operation of systems that control and control gear shifting. Also through this fluid is transmitted torque from the engine to the automatic transmission. Additionally, ATF-oil lubricates friction parts and cools them.

How to create fluid ATF

The first automatic transmission created in 1938year This design is called Hydramatic. She was different vacuum system gear. This unit was created by Pontiac engineers. Even then, the company was part of the General Motors carmaker.

Так как в General Motors перед запуском любой Innovative development preferred to pre-test it and test it in every possible way; a new automatic transmission was installed on the Oldsmobile. The tests went well. And now, in the 39th year, the Hydromatic was installed as an option on the Oldsmobile Custom 8 Cruiser. Such an option cost 57 dollars.

The role of General Motors in creating the first ATF

By the end of the 40s automatic transmission had become familiarpart of the car. And it is not surprising that the first ATF-oil for automatic transmissions was created by General Motors specialists. This was the world's first specification for transmission fluid. It was called Type A. The fluid was created in 1949. Then, GM began to develop gear oils, and later to classify, put forward the most stringent requirements for them. Products that were created in General Motots laboratories, due to the lack of competition, have become the international standard of working fluids for any type of automatic transmission.

From whale oil to new technologies

In 1957, the already successfully existing specificationrevised and decided to add one small new application - Type A Suffix A transmission fluid (short for ATF-TASA). After 10 years, created the specification B (this is ATF Dexron-B).

В качестве главного ингредиента, благодаря to which the fluid had lubricating properties, blubber was used - this is the fat that was obtained from whales. But then the development of technology in the production of automatic boxes forced the concern to introduce something new. So, in 1973, developed a new specification Dexron 2C. In 1981, it will be replaced by Dexron-2D. After a squall of negativity from animal defenders struck the corporation, and also after the whale catch ban, the company in 1991 creates an innovative formula for Dexron-2E. The difference of this product is that it is created on a synthetic basis. Previously, the lubricant was made on a mineral basis.

Birth of Dexron-4

In 1994, the entire world community learned aboutNew specifications, where new requirements for viscosity properties and temperature characteristics were stated. The specification also implied more improved frictional properties. These are Dextron-3F and Dextron-3G. After 8 years, Dextron-3H comes out. But the most modern and the most rigid is ATF Dexron-4. Of course, today there are other specifications from other automotive 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 go toquestion from afar. Automobiles use engine oil, gearboxes, hydraulic boosters and ATF oil. What are the similarities between all these fluids? The basis of these oils are hydrocarbons, which are obtained through the processing of minerals. This gives some similarities in the characteristics. All of these tools have lubricating properties, increase the slip between the rubbing surfaces.

Also, all these liquids have goodheat rejection characteristics. They are similar in consistency. That's where all the similarities end. This is sometimes the cause of gross errors, when a novice motorist pours oil for the "mechanics" in the automatic transmission, and brake fluid in the power steering.

The main properties of ATF

ATF oil is one of the most difficult.the composition of fluids among all the lubricants used in modern cars. To such a lubricant, there are high requirements and standards. Oil should have a lubricating effect - due to this, friction is reduced, and at the same time wear and tear in the gearbox elements is reduced. At the same time, friction forces in friction groups should increase. This will reduce the slippage of brake bands and other nodes.

Также одно из важных свойств – отвод тепла.The oil has high thermal conductivity and flow characteristics. In this case, the liquid should not foam in the process. An important point is stability, namely the absence of oxidative processes when heated to high temperatures at the moment of contact with oxygen. Additionally, the oil should have anti-corrosion properties. This is necessary in order to prevent the formation of corrosion on the internal nodes of the mechanism. Liquid for automatic transmission must be hydrophobic (this is the ability to push moisture from the surface). It is necessary that the fluid retains its flow characteristics and hydraulic characteristics. ATF-grease has stable characteristics and high compression ratio in the widest possible temperature range. Another moment - a decrease in penetrating abilities through the automatic transmission and the presence of the dye.

Typical specifications for automatic transmission lubricants

Consider a few specifications of ATF oil,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, the kinematic viscosity is not standardized at all, as well as for other specifications.

Вязкость масла ATF по Бруксфильду для 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. The flash point is not lower than 190 degrees for Dexron-2. For Dexron-3 - this parameter is 179 degrees, but not higher than 185.

ATF Compatibility

Любое масло (не важно, минеральное оно или synthetic), can be mixed without any consequences. Naturally, more modern liquids 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 the performance it will have. Also, the shelf life of ATF oil is much lower. Experts recommend changing this fluid every 70 thousand kilometers. It is worth noting that many modern manufacturers do not regulate the period of replacement of this fluid. It is filled for life. But when the car takes care of 200 thousand kilometers on one oil, it is not very good. The fact is that the fluid in the automatic transmission is working. It is she who transmits the torque from the engine to the wheels. This oil is constantly in action, even when the machine is at neutral speed. Over time, it collects production products.

This is a metal shavings, which clogs itselffilter and sensors. As a result, the box stops functioning normally. Now to the question of compatibility. No brand will ever fully disclose all the information regarding the composition and properties of the produced fluid. Often, manufacturers are limited to marketing information and advertising, forcing to buy only a specific product. But often this information is not justified. For transmissions with rigid engagement of the torque converter lock-ups, it is recommended to use fluids with constant friction characteristics. Для АКПП с блокировкой ГТФ следует заливать products with variable properties. And finally, regardless of the automatic transmission model, all parts, bearings, gears and other elements are made of the same materials. This means that the various types of ATF are not particularly different from each other.

About the features of the application and compatibility

If the oil in the box changes completely, thenbest to get a more expensive tool. In this case, it is necessary to take into account constant or variable friction characteristics. If the budget is limited, then even universal ATF oil will do. Its application will not affect the quality of the box. If the liquid is topped up, then experts recommend using products of a class higher or at least not lower than filled. But if its resource has reached 70 thousand kilometers, full replacement is necessary. It is advisable to make additional washing. This operation takes an additional 20 liters of oil. It is not cheap, but judging by the reviews, this operation perfectly washes out the chips. And its presence, as you know, makes it difficult for the automatic transmission.

So, we found out what ATF oil is for automatic transmission.