For most car owners, differential is a relatively unfamiliar term. We often talk about gasoline, engine oil, and brake fluid. Why is there a differential oil?

Old drivers generally call it axle oil, which is divided into front axle oil and rear axle oil. Simply put, this is a lubricant that acts on the front and rear differentials.

Regarding the differential, we won't be too nonsense. Listeners who don’t understand can download it on Baidu by themselves. In short, the car can turn normally without this mechanical structure.

Any mechanical structure on the car, as long as it involves gear engagement, needs oil to lubricate and cool down. Then this differential is no exception.

The reason why people don't know much about this differential oil is because it is not a regular option in the maintenance menu.

Here, Turbo Brother first tells everyone a conclusion: most private cars, the differential is maintenance-free for life. Generally speaking, the differential oil is in the dealer's place, which is an inspection item. It will only be replaced if there is a problem. There is no fixed replacement cycle.

If the car owner is very concerned about this, and feels that if the time is not changed, it will affect the driving texture, then it is usually replaced with the transmission oil at about 60,000 kilometers.

Otherwise, unless an oil leak or mechanical failure is found, there is no need to change the differential oil at all. However, special attention should be paid to the three types of models. Routine maintenance of the differentials of these three types of models is necessary:

The first type of vehicle is a four-wheel drive vehicle. You must pay attention to the maintenance of the differential. The differential oil should be replaced regularly, especially the rear axle differential oil. Generally speaking, the maintenance manual of four-wheel drive models will mention changing the differential oil. Because the transmission system of the four-wheel drive model is more complicated and has functions such as a limited slip differential, the mechanical structure of the differential is more complicated than an ordinary open differential and requires regular maintenance.

The second type of models are those hard-core SUVs, such as the Mercedes-Benz G-Class, where the differential oil must be replaced when the new car is 3000 kilometers away. Because this SUV with strong off-road performance is equipped with a differential lock, the maintenance of the differential is even more demanding. This SUV not only needs to replace the front and rear axle differential oil on time, but also regularly replace the lubricating oil in the central transfer case.

The third category of models is high-performance models, including front-wheel drive, rear-wheel drive and four-wheel drive. The high performance here refers to the kind of car with high horsepower and fast acceleration. As the speed of the car is too fast, the speed of the differential is also very fast, the lubricating oil immediately heats up, and it is often in a high load state, so more attention should be paid to maintenance than ordinary models. Take Tesla as an example. Although it is an electric car that does not need to change the oil, it needs to change the differential oil. The first change is 20,000 kilometers, and then every 40,000 kilometers.

If you are driving the above three types of cars, you must pay attention to the maintenance of the differential. Differential oil, which works continuously at fast speeds, and the temperature is very high, even exceeding 100°C. Continue to work under high temperature, the performance of the oil will decrease.

If you do not pay attention to maintenance, after the performance of the differential oil declines, the friction of the gears in the differential structure will increase, which will increase the fuel consumption of the car, and will damage the differential, differential lock and other devices for a long time.

If you are very particular about driving, you should also pay attention to the replacement of the differential oil when you drive a rear-drive car or a car that often drives at a high speed. But it does not have to be as demanding as the aforementioned three types of models. It will not be too late to replace low-end cars 100,000 kilometers away. For high-end cars, check it at about 40,000 kilometers. If there is no problem, it will not be too late to change to about 60,000 or 80,000 kilometers.

For the specific mileage to be changed, refer to the provisions of the maintenance manual and the specific vehicle condition. Compared with some cars that often run at high speeds or take bad roads more often, consider replacing the differential oil in advance to improve driving quality.

In fact, the composition of differential oil is somewhat similar to engine oil. When there was no special differential oil before, people used engine oil as the lubricating oil for the differential. With the popularity of some high-performance vehicles and the development of off-road vehicles, special differential oils have gradually entered the market.

Compared with engine oil, the function of differential oil is also lubrication, anti-wear and cooling, etc., and it must have better thermal stability than engine oil. Because the temperature of the lubricating oil in the differential is very high when driving at high speed, it will far exceed the temperature of the oil in the engine.

At this time, the high-temperature viscosity characteristics of differential lubricants are particularly important. This can be seen from the model of the differential oil. Like engine oil, differential oil, as a lubricating oil, also has a corresponding viscosity grade.

Here you just need to know a little bit! That is the choice of differential oil, which depends on the latitude, the south or the north, and the maximum load of the vehicle itself.