Transmission oils: classification and characteristics


Transmission oils - special classmachine oils, intended for use in different friction nodes of vehicle transmissions, as well as in various reducers. Motor and transmission oils are produced on a mineral or synthetic basis, and then alloyed with a variety of additives, but the requirements for transmission are higher, since they work at much higher loads and sliding speeds of rubbing surfaces.

Transmission Oils
One of the most important indicators of such oilsis the ability to create a protective film on the surface of the friction units to prevent mechanical contact between them. In hypoid gears, oils are used that, when reacting chemically with the surfaces of parts, prevent their skipping, have anti-seize properties. During operation, the transmission oils oxidize and become contaminated, so they must be periodically changed. Good oil is considered to be an oil with a low tendency to oxidation. Since different manufacturers use different additives, their products can not be mixed. When replacing the transmission assembly, it must be thoroughly rinsed, if possible with the same fresh oil.

Classify gear oils orviscosity, or performance properties. So on SAE (Association of Automotive Engineers) they are divided into nine classes - five summer and four winter (with the index W). For each class, the viscosity index is indicated. SAE 70W or SAE 250, for example. For all-season oils, a double index is indicated (SAE 80W-90, etc.).

API (American Petroleum Institute) sharesOil for 6 classes depending on the operational properties - GL-1 ... GL-6. These classes are similar to those used in the Soviet GOST 17479.2-85 TM1 ... TM6. The fifth and sixth groups are used for hypoid gears and have the highest lubricating and extreme pressure characteristics.

motor and transmission oils

When choosing transmission oils,focus on the conditions of their work. If the class is lower than necessary, the mechanism will simply fail, and a higher grade of oil will have a higher cost, which will lead to a cost overrun. It is also important to consider at what temperatures the transmission will work, and proceeding from this to select the lubricant. SAE 85W, for example, will operate at temperatures down to -12 ° C, and 85W already up to -40 ° C. In automatic transmissions a special low-viscosity liquid is used, therefore neither motor nor transmission oil is used there.

transmission oils
Today the market a large range of manufacturersoffer their transmission oils - Lukoil, Total, Texaco, Rexol, Norsi and many others. The variety of additives used determines both the quality level of the oils and their price range. Mineral, usually, is cheaper, but it serves less, synthetics are exactly the opposite. A good compromise in this case will be semisynthetics, as the golden mean between the first two. Also, you should be careful not to make fakes and not buy oil in unchecked stores. Changing the box is always more expensive than taking a good, quality oil, especially since now they are nursed from 60 thousand or more kilometers from replacement to replacement.

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