​All you need to know about transmission oil

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​All you need to know about transmission oil

A car transmission is a very complicated mechanism consisting of numerous parts. The parts are wearing out because of friction and high temperatures when operating, consequently the scratches appear. Transmission oil reduces friction as well as removes heat. It is due to the formation of a stable protective oil film on the surface. It is necessary to provide a quality lubrication of all the parts for the proper operation of car units. The gear box needs transmission oil just like the engine needs motor oil. 

Peculiarities of use

Transmission oil is necessary for gear boxes, transfer cases, drivetrains as well as for steering gears. Transmission oil should be replaced as regularly as motor oil. On average, it should be changed each 75–150 thousand km travelled. 

Transmission oil performs protective functions lying in formation of the stable oil film on the surface of the mechanisms. Besides, the oil minimises frictional losses, removes heat from the surfaces involved in this process. The protective functions also lie in the fact that oil prevents corrosion as well as removes wear products. Moreover, the good transmission oil reduces shock loads on gearwheels as it seals air spaces between surfaces undergone friction. Summing all the above up, we can draw the clear conclusion that one shouldn’t underestimate the role of transmission oil in proper operating of the vehicle and prolonging of its service life even considering its small quantity to be applied. All drivers should choose quality products and timely change the transmission oil. 

Transmission oil change: reasons

Transmission oil as well as the motor oil consists of the base and additives package. During the period of operation, the oil loses its properties as the additives are getting worn out and the protection of the gearbox parts is getting worse. The old oil does not guarantee proper protection of cartridges, bearings and plates. They are overheated, deposits of carbon accumulate on them, as a result the gear change becomes worse. The temperature in the gearbox can reach 150°C, consequently the old oil foams and does not perform its functions anymore. The foamed oil interferes with the torque transfer and the vehicle stops. The first reasons for changing oil lie in humming and then in gradual destruction of gears. 

How can we define that it is time to change oil?

Oil should be changed within a specified term, singled out in the service book by the manufacturer. The mileage of 40-50 thousand km is usually indicated. The driving style also matters. The oil degrades after 20-30 thousand km travelled under aggressive driving style with rough starting, towing and stopping. 

How to choose a right oil for the gearbox? 

There are various types of transmission and there is an oil for each type. The fluids for automatic, mechanical and infinitely variable transmissions differ in viscosity, additives quantity and temperature range of the operation. The transmission oil can be synthetic and mineral one, consisting of detergent, antiscoring, anticorrosion and other additives. These components prolong service life of transmission and oil. 

The oil should be chosen in accordance with the requirements of vehicle manufacturers or considering two criteria: unit load and relative slip speed. The oil with certain viscosity and additives content should be chosen depending on this. When choosing the oil pay attention to what transmission it is designed for. The oils also differ in seasonal prevalence, however most of modern oils are multi-purpose and can be applied at the temperatures ranging from -50°C up to +50°C  without losing of its properties under cold and hot weather. A degree of quality marked with GL and figures from 1 to 5 on the canister is another important indicator. The oils of the degree of quality not lower than GL 4 are applied for modern vehicles. They are imposed with the requirements concerning antiscoring and antiwear properties. Unsuitable oil can result in serious break of the transmission. We encourage following the recommendations of manufacturer when choosing the oil.