Why it is useful to violate the maintenance schedule for a car gearbox

The oil in the gearbox, almost all automakers claim, is filled for the entire life of the car. But what does such a phrase really mean, which can be found even in the car’s service book, and when to change the oil in a “maintenance-free” gearbox, the AvtoVzglyad portal figured out.

If earlier gear oils were made on a mineral basis, now they are produced on a semi-synthetic or synthetic basis. That is why, on old machines with an "automatic", the manufacturer recommended changing the lubricant in the gearbox after 30-000 km of run. "Mineral water" after all serves less than "synthetics". Now the recommendation has disappeared, but synthetic gear oils also have their own service life. Let's take a look at these nuances.

Now, more and more often, the annual mileage of a car is no more than 30 km, and the estimated life of the car is about six years. So it turns out that the resource of most cars, according to automobile companies, is 000 km. It follows from this that the oil in the gearbox still needs to be replaced, otherwise the transmission may break. And not only a gentle “robot” or a variator, but also a fairly reliable hydromechanical “automatic”.

The fact is that over time, transmission wear products clog the filter surface to such an extent that the pressure in the system drops. So much so that the actuators stop working properly. Plus, heavily contaminated gear oil leads to wear of most gearbox components: bearings, gears, valve body valves.

Therefore, the replacement of oil and filter in an automatic transmission must be carried out after 60 km of run. Thus, you will exclude the so-called overrun, in which the lubricant has already exhausted its resource, and the additives added to it have stopped working. This can be determined by the appearance of beating and shocks when shifting gears, vibrations and a decrease in vehicle dynamics.

Well, if the car is operated in difficult conditions or they like to drive on it, it would be good to change the fluid in the “machine” even more often - after 40 km. So an expensive unit will last longer. It will not be superfluous to replace the fluid in a used car, and immediately after purchase. After all, there are no guarantees that the previous owner took care of the car.