1.the engine speed increases quickly when the car steps on the accelerator, but the speed does not change
This situation belongs to the gearbox slip, the feeling in the flat road in the early stage of failure will not be too obvious, after a long time, it can be obviously felt, especially in the uphill, step on the accelerator speed up the car speed is not lifted, this time on behalf of the gearbox has a slight slip, remember not to try the big foot throttle rush slope, otherwise it will cause more serious wear of the gearbox. It's about getting to the repair shop and checking the gearbox as soon as possible.
There are two directions to check, the first is to see if there is any leakage of transmission oil, because the automatic transmission relies on the internal lubricating oil to act as the medium oil, thereby establishing a certain oil pressure and promoting various valves to work. If a part of the transmission oil is missed or the oil deteriorates, it will lead to insufficient oil pressure, and the transmission is easy to slip. The solution is relatively simple, replace the transmission oil or add a little transmission oil.
There are two directions to check, the first is to see if there is any leakage of transmission oil, because the automatic transmission relies on the internal lubricating oil to act as the medium oil, thereby establishing a certain oil pressure and promoting various valves to work. If a part of the transmission oil is missed or the oil deteriorates, it will lead to insufficient oil pressure, and the transmission is easy to slip. The solution is relatively simple, replace the transmission oil or add a little transmission oil.
2. Automatic transmission high temperature alarm;
This situation should be said to be more common, especially the old DCT gearbox, that is, the dual-clutch gearbox, under normal circumstances, there will be prompts on the high temperature alarm dashboard.
There are two reasons for the high temperature of the gearbox. The first reason is that multiple groups of friction components inside the gearbox continue to work, resulting in heat exceeding the heat dissipation limit of the gearbox, such as the dual-clutch idling for a long time, and this problem will occur when continuous stop-and-go. Do not continue to drive after the gearbox high temperature alarm, find a safe place to park the car, let the gearbox cool down naturally.
The second case is that the gearbox itself does not have any problems, and the heat does not exceed the standard, but because the coolant of the car has not been replaced for a long time, the impurities inside blocked the coolant water of the gearbox oil cooler, resulting in the transmission oil having no way to cool down through the coolant, and ultimately resulting in the high temperature of the gearbox. This situation is more troublesome, not only to replace the coolant of the whole car, but also to wash the coolant pipeline to be able to solve.
But no matter what kind of high temperature situation, as long as the gearbox high temperature alarm failure light exploded on the dashboard, do not continue to drive, because the friction components of the gearbox have a maximum temperature threshold, beyond this temperature, the probability of their damage is 100 percent, so find a safe place to park the car. It's not too late to take it to the repair shop when the temperature drops.
3.the gearbox lifting speed is slow.
For example, your car was originally 1500 shift gear when it stepped on the accelerator at a constant speed, but gradually began to shift into 1800 or even more than 2000, which is a typical shift delay, and most of the reasons for this situation are caused by insufficient transmission oil pressure.
Because there are many electromagnetic valves in the automatic transmission, such as lubricating pressure solenoid valve, torque converter lock regulator, brake regulator, clutch regulator, booster shift valve, working pressure regulator, etc., they all need transmission oil to establish working pressure. Once the oil is not changed for a long time, the transmission oil deteriorates or impurities increase, and the oil becomes viscous. It will lead to insufficient oil pressure of the solenoid valve, and the overall response of the gearbox will be slower and slower, resulting in a delay in the lifting gear.
The solution is also very simple, my personal suggestion is to try to use artificial gravity oil change to the transmission oil, the advantage of this is that the old oil will not be completely cleaned at once, and then gravity change once after driving thousands of kilometers, so that the transmission gradually adapt to the viscosity of the new transmission oil, so as to gradually restore the speed of the lifting gear.
4.the car speed up or accelerate when the big and small "whistle";
This kind of sound is generally due to the wear of the parts of the metal and metal friction inside the gearbox, such as the bearing, cylinder block, gear, cone wheel and other parts are ground out some uneven small gaps, the formation of these gaps is mostly due to the failure of the defoamer in the transmission oil, resulting in a large number of bubbles after the transmission oil is violently stirred. The areas that were originally to be lubricated by the oil film were filled with bubbles, which eventually led to metal "cavitation" in these areas, resulting in the formation of abnormal transmission sounds.
This situation is no way to repair, want to completely eliminate the abnormal sound, can only replace the transmission parts, and even the entire transmission assembly, so when you hear the gearbox has such a little abnormal sound, you must hurry to check and maintain.
5.the car acceleration failure is more and more obvious;
When the gearbox fails, you will feel that the car will jump forward when accelerating the shift, which is because the gearbox solenoid valve works abnormally, or the work lag is caused by the reason that the gearbox oil has not been replaced for a long time, resulting in too much oil that blocks the solenoid valve pipeline.
For example, the original gearbox is a first gear up second gear, second gear up third gear, as a result of not replacing the transmission oil for a long time, the solenoid valve of the second gear is blocked, and the first gear directly rises three gears, then at the moment of shifting, you will feel the car suddenly leap forward.
The solution is to try the gearbox depth oil change first, if there is a flop, and then try to replace the faulty solenoid valve separately, the general price is not too expensive.
But if your car has been paralyzed for a long time, then the probability that the valve core of the gearbox valve body has been completely blocked, in this case, you can only replace the assembly of the gearbox valve body, and the price is similar to changing a gearbox, so if you feel that the car has an obvious frustration, then it is still possible to check and maintain as soon as possible.
