Gear oil 80W90. Tolerances and operating parameters
Liquids for Auto

Gear oil 80W90. Tolerances and operating parameters

Deciphering gear oil 80W90

Let us briefly consider the main characteristics that gear oils with a viscosity of 80W90 have. The SAE J300 standard says the following.

  1. The pour point before the loss of lubricating and protective properties is at the level of -26 ° C. When freezing below this temperature, the dynamic viscosity of the oil will exceed the acceptable limit of 150000 csp accepted by SAE engineers. This does not mean that the grease will turn into ice. But in consistency, it will become like thickened honey. And such a lubricant will not only not be able to protect the loaded friction pairs, but in itself will become an obstacle to the normal operation of the unit.
  2. The kinematic viscosity at 100 °C for this class of oil must not fall below 24 cSt.. It sounds strange in relation to the transmission units: the temperature is 100 ° C. If the gearbox or axle warms up to such a temperature, then most likely there are some problems in the transmission assembly, or the permissible load has been exceeded. However, the viscosity at 100 °C is taken into account here, because the oil film is under enormous stress in the contact patches and can locally be heated to higher temperatures. And if the viscosity is insufficient, then the film will break down more easily and allow the metal to contact the metal directly, which will cause accelerated wear of the assembly parts. Indirectly, the “summer” part of the index determines the maximum allowable summer temperature, which for the oil in question is +35 °C.

Gear oil 80W90. Tolerances and operating parameters

In general, viscosity is the main indicator. It is he who determines the behavior of a particular gear oil in different temperature ranges.

Scope and domestic analogues

The scope of 80W90 gear oil is limited not only by temperature limits, but also by other properties, such as: the ability to form a strong film, resist foaming and oxidation, service life, aggression towards rubber and plastic parts. These and other properties of gear oil are described in more detail by the API standard.

Today in Russia, 80W90 gear oils with API classes GL-4 and GL-5 are more common than others. Sometimes you can also find GL-3 class lubricants. But today they are almost completely discontinued.

Gear oil 80W90. Tolerances and operating parameters

Oil 80W90 GL-4. It is used in most synchronized gearboxes and other transmission units of domestic and foreign cars. Interchangeable with GL-3 class oils, but contains a more advanced package of additives, in particular extreme pressure additives. It has good lubricating and protective properties. Able to work with hypoid gears, in which the contact load does not exceed 3000 MPa.

Gear oil 80W90 class GL-5 according to API has replaced the class GL-4, already obsolete for new cars. Reliably protects hypoid friction pairs with a large displacement of axes, in which contact loads exceed 3000 MPa.

However, this oil may not always be used in gearboxes designed for the GL-4 standard. It's all about the very low coefficient of friction, which is achieved through an advanced additive package. Synchronizers of simple manual transmissions work due to the coefficient of friction. That is, the synchronizer is pressed against the gear and equalizes the speed of rotation of the shafts immediately before the gears enter into gear. Thanks to this, the transmission will turn on easily.

Gear oil 80W90. Tolerances and operating parameters

When running on GL-5 oil, synchronized gearboxes that are not designed for this standard often experience tight gear changes and a characteristic crunch due to synchronizer slippage. Although the car owner can see some increase in car power and a decrease in fuel consumption due to a noticeably lower coefficient of friction. Also, synchronizers fail at an accelerated pace on boxes that are not designed to work with GL-5 oil.

Other transmission units that require simple lubrication of the force-transmitting mechanisms may be filled with GL-5 oil instead of GL-4.

The price of 80W90 oils starts at 140 rubles per 1 liter. This is how much the simplest domestic lubricants cost, for example, the OilRight brand. The average price tag fluctuates around 300-400 rubles. The cost of top products reaches 1000 rubles per liter.

The domestic version of 80W90 oil according to the old classification is called TAD-17, according to the new one - TM-4-18 (similar to 80W90 GL-4) or TM-5-18 (similar to 80W90 GL-5).

Transmission oil G-box Expert GL4 and Gazpromneft GL5 80W90, frost test!

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