Oil with precision! What kinds of gearbox are there? Why can't you use the same gearbox oil?!

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Oil with precision! What kinds of gearbox are there? Why can't you use the same gearbox oil?!

Automobile transmission oil is an indispensable oil to ensure the normal operation of the gearbox. With the continuous progress of automobile manufacturing, the gearbox is also divided into many types, and the transmission oil is also various.

I believe that many owners also have questions: transmission oil plays the same role, that different transmission oil can be mixed? Let's talk about that.

Transmission oil characteristics and differences

In fact, the setting of each transmission has different technical requirements, even if the same model of transmission is configured in different models, its torque, weight, speed, structure, etc., will be different, so the original factory has its own designated special transmission oil. The different transmission oils are one of the reasons that affect the shift quality and the durability of the gearbox.

The most fundamental difference of transmission oil is the difference in its friction coefficient. Automatic transmission oil has more delicate oil molecules and efficient anti-shear ability. In the semi-clutch state or at the moment of combination, the oil film acting on the surface of the friction material can play an effective suspension buffer effect, which can moderate the powerful impact force and make the combination smoother.

Classification of transmission

The gearboxes on the market are roughly divided into five categories: manual (MT) gearbox, automatic (AT) gearbox, AMT gearbox, CVT transmission oil and DCT gearbox, and the oil used in different gearboxes is also different.

1.AT gearbox

Definition: AT automatic transmission is composed of hydraulic torque converter, planetary gear and hydraulic control system, through the combination of hydraulic transmission and gear to achieve variable speed and torque. A car equipped with an automatic transmission can automatically change speed and torque according to road conditions.

Transmission oil: AT transmission oil, is specifically used for automatic transmission of the oil, it has two roles, one is the planetary gear set lubrication, heat dissipation, the most important is to transfer power, so its viscosity is relatively lower than manual transmission.

The second is responsible for hydraulic transmission, so the liquidity requirements are higher, and the anti-bubble ability is more stringent than the manual transmission oil requirements. AT is now mainly 4AT, 6AT, 8AT, 10AT, etc., the transmission oil models used are also different, and the more the gear, the higher the requirements for AT transmission oil.

2.MT gearbox,

Definition: MT manual transmission, also known as the manual shift, that is, the hand to move the gear lever to change the gear mesh position in the transmission, change the transmission ratio, so as to achieve the purpose of speed change.

Advantages and disadvantages: simple structure, low cost, driving fun Disadvantages: cumbersome operation, switching gears will have obvious frustration, in the city congested sections or traffic jams, the driver is easy to tire.

Transmission oil: MT transmission oil is usually referred to as gear oil, which is mainly used for lubrication and heat dissipation. According to its quality level, the American Petroleum Institute classifies gear oil into 5 grades, from GL1-GL5. Due to the low quality requirements of GL1-GL3, it has been discontinued, and only GL4 and GL5 are generally sold on the market. From the characteristics of the oil, the viscosity is relatively large, and the replacement cycle is generally shorter.

3.AMT gearbox

Definition: AMT automatic clutch transmission is an electromechanical hydraulic integrated automatic transmission that integrates the advantages of AT (automatic) and MT (manual) based on the traditional manual gear transmission.

Advantages and disadvantages: Advantages: high transmission efficiency, low manufacturing cost, simple structure, low fuel consumption Disadvantages: large shift impact, poor comfort.

Transmission fluid: AMT transmissions can generally use MT transmission fluid. Its working principle is improved on the basis of the original mechanical transmission (MT), mainly changing the manual shift control part, that is, in the case of the overall transmission structure unchanged by installing a microcomputer control automatic control system to achieve shift, therefore, AMT can be used with MT a common transmission oil. Of course, some AMT transmissions will use special AMT transmission oil, and MT transmission oil cannot be used.

4.CVT gearbox

Definition: CVT endless transmission, as the name suggests, there is no clear gear distinction, according to the road conditions and the actual use of the vehicle, by changing the transmission ratio of the engine power and fuel consumption are controlled in an optimal range, so that the power output continues to flow smoothly.

Advantages and disadvantages: Advantages: the shift is very smooth, the power is continuous and smooth, and the fuel consumption is also good. Disadvantages: acceleration is slightly poor, lack of driving pleasure, can withstand the maximum torque is small. It is not suitable for powerful torque models, and the power response is slightly slower.

Transmission oil: The essence of CVT oil is similar to AT, but it is also specialized oil, because CVT is a special steel chain transmission, the flow rate of oil, friction performance, coefficient of expansion and other values are different, so it can not be replaced by AT oil, relatively speaking, it is lower than the viscosity of AT oil, in addition, it has a certain damping friction to prevent the transmission chain from slipping.

5.DCT gearbox

Definition: The DCT is a dual-clutch transmission. Some people also call it DSG, which ostensibly means "direct shift transmission" in Chinese. Because it has two sets of clutches, it is called "dual-clutch transmission".

Advantages and disadvantages: Advantages: the shift is smooth, there is no general automatic transmission shift frustration. Fuel saving and efficient use of kinetic energy generated by the engine, advanced technology. Disadvantages: complex transmission structure, high maintenance costs; Years of research and development test quality gradually stabilized, but some new car users due to failure to replace the DSG gearbox; The gearbox is overheating and performance is declining.

Transmission oil: Although the DSG dual-clutch transmission is also called automatic transmission, it is fundamentally different from the previous automatic transmission. DSG can be understood as a combination of two MT, so the oil used in the transmission is gear oil and hydraulic oil, which are also specialized supplies and cannot be mixed with other transmission oil.

Precautions for replacing transmission oil

Special attention should also be paid to the replacement of transmission oil. Due to the different components in various transmissions, the required oil flow rate, density, friction and expansion coefficient are different. If the wrong transmission oil is added, it will not only cause wear and tear to the electronic components and metal components in the transmission box, but also cause damage to the gearbox seal.

In addition, because different transmissions are only equipped with one transmission oil, and each transmission oil will have a different label, so when it is necessary to replace transmission oil, it must be changed in strict accordance with the variety and label said in the manual, and it is recommended to replace it every 2 years or 40,000-60,000 kilometers.