When to change the transmission fluid in an automatic transmission
An oil change is a familiar process for every motorist, but only when it comes to the motor. If we talk about changing the oil, or rather the fluid in an automatic transmission, then many questions immediately arise. When to change and how to change are the main ones, but it is also interesting whether this should be done at all, because often manufacturers declare that the oil inside is designed for the entire service life. View here for more info: too much transmission fluid
Why is fluid in the gearbox
First, it is worth understanding what the viscous liquid inside the machine is responsible for. Note that now we will only talk about classic automatic transmissions. Transmission fluid in an automatic transmission performs several fairly important functions at once. First, it is a working fluid for the hydraulic system. Gears are switched by fluid pressure inside. Secondly, it cools the insides of the automatic transmission, and thirdly, parts are lubricated, the same bearings, for example.
What's going on with ATF
Over the years, the transmission loses its properties: additives are produced, the viscosity decreases. Plus, the waste products of the gearbox get into the slurry. The automatic transmission contains a large number of friction pairs that cause inevitable wear. These are microparticles of clutches, as well as other internals of the unit. Over time, they can clog the valve body channels. Overheating of the fluid promotes aging.
When to change
Here, in fact, we come to the first controversial issue. A couple of decades ago, one could say for sure that the oil changes every 30-60 thousand kilometers. However these days some car manufacturers claim that ATF is filled for the life of the box. True, there are reservations in this statement. The manuals still prescribe the replacement frequency for severe operating conditions. Moreover, they mean not only some serious off-road, but also ordinary traffic jams. In fact, operating a car in Kazakhstan can be classified as difficult and follow the recommendations of the manual.
The Toyota Camry XV70, for example, has a fluid change every 80,000 km or every four years, and the Hyundai Accent says: "Does not need inspection and maintenance," but a separate table says the interval of 100,000 km when driving on dusty, mountainous or busy roads.
How to change
This is the second controversial point. A lot of copies of ATF replacement methods have been broken. There are two main ways: partial replacement and complete with the help of special equipment. What is the difference between these methods, it is obvious from the name, but the question immediately arises: why change only a part of the oil, if dirty residues will still mix with fresh liquid?
This method is often recommended to be used on not the most recent gearboxes, especially if the date of the previous oil change is unknown. It is believed that several of these procedures allow you to completely update the ATF without a sharp change in the characteristics of the fluid and the risk of clogging with wear products that settle on the walls of the system and valve body. The last trouble is blamed on the detergent additives that fresh ATF is rich in.
During the procedure, all available oil is drained from the gearbox with the removal of the sump (if any). In some cases, this is about half of the total volume. That is, if 10 liters are poured into the vending machine, then there will be about five liters in the waste tub. Also, the gasket is changed and the magnets are cleaned to catch metal chips. Most often, the latter are placed on the drain plug. After a short run on a diluted liquid, the procedure is repeated.