Transmission oils are used to lubricate gearboxes, gearboxes, gears, transfer cases and other parts. Their main function is to create a strong lubricating film around parts. They have a large number of additives, thanks to which the oils are multifunctional and can maintain their performance for a long time.
But over time, even the most expensive oils lose their properties. To ensure that the gearbox always functions smoothly and the parts themselves do not wear out, you need to change the gear oil on time.
The main reasons for changing transmission oil:
- failure of the gearbox and gears;
- clogging of the gearbox;
- unpleasant sound, noise, knocking in the gearbox;
- formation of carbon deposits around parts (in this case it is better to change the manufacturer rather than just add fresh oil);
- complications of gear operation at low or high temperatures;
- oxidation or corrosion phenomenon.
You also need to choose an oil that is suitable for a specific car and meets all specifications - then both the oil and the gearbox will last a long time.
Oil shelf life
Each oil has its own composition and, accordingly, a certain operating time. The final sell-by date for unopened, unused oil is indicated on the packaging by the manufacturer. Basically, oils with a good stable composition can last up to 5 years without losing their properties.
You also need to take into account the storage conditions of the closed jar.
For example, excessive heat accelerates oxidative processes, and cold leads to the formation of unnecessary deposits. It is better to store gear oil in a dry, clean place, at a temperature no higher than 25 degrees and no lower than 10, otherwise it will change its viscosity and other properties.
During operation, the shelf life of the oil depends on various conditions: the load of the vehicle itself, its specifications, temperature conditions, mileage, speed, etc. Under average loads, gear oil can be stored for no more than two years. At the same time, it must be constantly checked for oxidation, carbon deposits and viscosity. Under heavy loads, more time must be devoted to changing the oil, since the condition of the gearbox depends on this.
With the advent of modern automatic transmissions, the issue of protecting mechanisms and assemblies became acute. Oils for manual transmissions were unsuitable because their characteristics did not meet the necessary requirements. An automatic transmission, like a manual transmission, changes gears, but the automatic transmission operates independently, and this greatly complicates its design. In addition, the operating conditions of the mechanisms and components of the machine do not correspond to the operating conditions of the mechanics, so a new ATF type of lubricant was developed for it.
ATF lubricant
ATF fluids are special oils used for operation in automatic transmissions with a hydraulic transformer, as well as in some models of CVTs. The abbreviation for lubricants stands for: ATF (Automatic Transmission Fluid, fluid for automatic transmissions). The purpose of the lubricant is to protect the internal parts of the box from corrosion, overheating and wear; in addition, the liquid transmits impulse from the transmission power unit. Liquid lubricants with increased fluidity, mineral or synthetic base.
Transmission fluid performs the following functions:
- Monitoring and control of automatic transmission;
- Cooling of parts and mechanisms;
- Formation of a protective film on the surface of parts;
- Corrosion protection;
- Preventing early wear of mechanisms from friction forces;
- Transfer of impulse from the power plant to the transmission;
- They help the friction discs work.
Working fluid in manual transmissions and ATF oil for automatic transmissions, lubricants that are not similar to each other. The performance of ATF fluid differs from conventional oil in many ways. To create the desired consistency, mineral oils are used, adding special additives to them. Each automatic transmission is suitable for a certain type of oil, with its own set of characteristics. Using an inappropriate fluid will inevitably lead to failure of the mechanism, which is why it is so difficult to choose a product similar to the original.
For the first time, the specification of transmission lubricants was introduced into use in 1949. The concern that proposed to do this, General Motors, had no competitors or analogues at that time, and ATP fluid was specially developed for the automatic transmission designed by the company. Currently, the following companies are developing and standardizing transmission fluids: Hyundai, Toyota, Ford, Mitsubishi, GM.
Types of ATF fluids
The first type of ATF in automatic transmissions was produced by GM, it was called ATF-A. In 1957, modernization was carried out and a new liquid called Type A Suffix A appeared.
Types of ATF fluids on the market today:
- The Mercon type, developed in 1980, was carried out by the auto manufacturer Ford. Compatible with other types of lubricants, since their characteristics are identical. The difference from competitors is the calculation for the use of fluids in mechanisms where speed is required when changing gears.
- Beginning in 1968, GM began producing a lubricant called Dexron. The liquid did not tolerate high temperatures, in addition, it was based on whale fat, so production was soon stopped. Since 1972, the type was replaced by a new fluid called Dexron IIC, but the product was prone to creating corrosion in some box components, so it was also replaced by Dexron IID, which used anti-corrosion additives. Until 1993, GM produced oil with the IIE prefix, which was famous for its ability to minimize the amount of moisture in the box. GM gained fame with the release of Dexron III fluid in 1993. The product had increased fluidity and performance at low temperatures, as well as improved properties with respect to rubbing surfaces. Used for power steering and hydraulic systems. In 2005, a new liquid with index IV was released. The product was developed for a six-speed gearbox and has improved performance, extended service life, and increased fuel efficiency.
- Alison C-4 lubricant, used on trucks and construction machines.
Toyota has developed ATF WS fluid specifically for automatic transmissions of Toyota and Lexus cars. Successfully used in automatic transmissions and automatic transmissions with manual shift capabilities. ATF WS Toyota lubricant is a priority when it comes to its use on cars manufactured by the company.
Replacing ATF fluid
Transmission fluid is a consumable item that needs to be changed periodically. Timely replacement of ATP in automatic transmissions increases the service life of transmission parts and mechanisms, because during operation they are subject to increased wear, the products of which settle in the oil.
Conditions affecting the oil change interval:
- Intermediate vehicle mileage between fluid changes;
- The environment and conditions in which the vehicle was operated;
- The nature of operation and driving style of the vehicle.
The design of automatic boxes requires the mandatory removal of the tray and cleaning of the magnets from metal shavings and accumulated debris. When changing the oil, the filter element must also be changed to remove impurities and ensure the liquid is cleaned in the future.
It is advisable to carry out the procedure at branded service stations equipped with special devices for pumping out remaining liquid from the system. Carrying out the operation yourself will only allow a partial replacement of the fluid, which can have a detrimental effect on the operation of the unit in the future.
Checking the ATF level in the box
The quality of function performance and the service life of the box directly depend on the level of lubricating fluid in the product. The procedure for checking the oil level is carried out regularly, since deviation from the established standards entails unpleasant consequences:
- Lack of oil leads to air bubbles being picked up by the pump and rapid wear of the clutches in the future. They also burn, which disables the system.
- An excess of lubricant leads to its leakage through the ventilation valve, which can lead to the loss of a significant amount of fluid and also failure of the clutches.
The liquid level on each box model is monitored in accordance with the requirements. Before performing work, you must read the documentation for the product and carry out the procedure strictly following the established regulations.
Selecting fluid according to ATF specification
- Dexron B: the first specification of ATF fluids, developed in 1967;
- Dexron II: development began in 1973, the standard received worldwide recognition;
- Dexron IID: introduction began in 1981, intended for automatic transmissions operating at temperatures not lower than -15°C;
- Dexron IIE: introduction began in 1991, designed for automatic transmissions operating at temperatures down to -30°C. Synthetic base, improved viscosity characteristics;
- Dexron III: introduced in 1993, designed for use in modern boxes, increased requirements for viscosity and friction;
- Dexron IV: Synthetic product, filled into modern boxes.
The Ford company also has a specification, its name is “Mercon”, but the marking is not widely used; it is unified with the GM specification. For example: DesxronIII / MerconV.
Chrysler also specifies its products, the specification is called "Mopar". It is not common in our region, and if it is found, it is also unified with Dexron.
Mitsubishi (MMC)-Hyundai classification:
- Type T (TT): used in A241H and A540H all-wheel drive gearboxes produced in the 80s;
- Type T-II: designed for electronically controlled automatic transmissions produced in the early 1990s;
- Type TT-II: automatic transmissions with electronic control from 95-98;
- Type TT-III: automatic transmissions with electronic control from 98-2000;
- Type TT-VI: automatic transmissions with electronic control after 2000;
- ATF WS: a generation of synthetic lubricants used in modern transmissions manufactured by Toyota.
Incorrect selection of the mixture entails a large number of breakdowns, so it is necessary to refer to the documentation for the product and follow the recommendations that are written there.
Interchangeability of ATF fluids
Important! Toyota ATF WS transmission fluid is not interchangeable with fluids produced by Toyota and Dexron. WS grease has the ability to absorb moisture, so the storage container is opened only once.
If necessary, ATF WS gear lubricant is replaced with oils of similar characteristics from third-party manufacturers: Idemitsu, Aisin, Zic.
When changing the lubricant in an automatic transmission, you must remember that modern transmission fluids are a mixture of components in a certain proportion, each of which individually represents the final product. The settings of modern automatic transmissions after 2003 are sensitive to changes in components and take into account their specifics during operation. Thus, if there is any doubt about the type of old oil, it must be completely replaced.
You can take a long time to determine the viscosity of the oil, pedantically compare all the recommendations, carry out the most rigorous selection among brands, but if you overlook the expiration date, then all previous work is simply offset by the result that is the opposite of the desired effect.
If you try to identify the main reasons why oil can go bad, the picture will look something like this:
- Oil must be stored in places without direct sunlight
- oil is a flammable product, so high room temperature is extremely undesirable (no more than 60 degrees)
- High indoor humidity significantly reduces its shelf life
- Oil can be stored in a closed container for up to 5 years, and in an open container for 3 years.
- All motor oils are hygroscopic, i.e. have the ability to absorb moisture from the room - this is a direct path to loss of properties and qualities
Determine if the oil has gone bad 
If the engine or transmission oil has a clear sediment, it has become uneven or has changed color - this is a clear sign that it needs to be disposed of. In everyday conditions, it is impossible to restore the properties of such a lubricant, since the factory undergoes a series of procedures, including heat treatment. And hardly anyone would want to experiment on their car by adding oil after home experiments.
VIDEO: Rules for storing automobile oils
Conditional shelf life of various types of oils
- Mineral-based base oil shelf life - 3 years from the date of bottling
- Semi-synthetic and synthetic lubricants for various purposes, in sealed original containers - 5 years from the date of bottling
- Compressor and hydraulic oils – 2-3 years (depending on the manufacturer) in a closed factory container
How often to change engine oil if mileage is short
Probably the most frequently asked question from motorists. The answer to this lies, as always, on the surface. 
We recommend that you adhere, first of all, to the recommendations from the factory and logic. It is the car manufacturer's recommendations on the frequency of replacements, most optimally take into account the design features of the engine and the properties of the oil used.
You have already read about the storage period and methods in this article above. Well, if, for example, you don’t have time to cover 10 thousand kilometers in a year, then in theory, you can continue driving until the specified period. Although, practice is such that few people can say exactly what chemical processes occurred with motor oil during this period? Isn’t it cheaper and safer to make a replacement? Of course it's up to you to decide...
Important!
Storing motor oil in a canister and in a car engine is not the same thing. The aging period and loss of properties are reduced significantly. The reason for this is constant contact with fuel and reaction with old used oil, which inevitably remains in a small residue during replacement.
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