The automatic transmission in a car is structurally complex and fragile unit, requiring careful attitude and quality service. Often, serious damages of such transmission are explained by the “human factor” and gross mistakes during exploitation. It is possible to kill an automatic transmission for a couple thousand km of run, if the main rules and practical recommendations are ignored. Let us consider the list of the most widespread actions, threatening the integrity of automatic transmission.
Extreme modes of operation
Frequent acceleration in “gas to the floor” mode, attempts to get out of mud or snow, transportation of large-size trailers or towing other machines – all this provokes increase of transmission fluid temperature, which is not just a lubricant, but also the working substance for the hydraulic system and torque converter.
The composition performs cooling of the unit. Oil heating also occurs when the radiator is clogged or oil pressure drops due to pump failure. However, the cause of overheating is often the car owner’s wrong approach.
Constant loading causes the oil to heat up and lose its initial performance properties. If it starts to burn, it causes a sludge that clogs the solenoids and the hydroblock. Also the friction clutches are at risk.
It is important to note that some models of automatic transmissions, such as Renault DP0, where a miniature heat exchanger is installed, are very vulnerable to overheating. In the case of an increase in operating temperature, they go into emergency mode or require overhaul. Among the main signs of boiled box are jerks and jerks when changing gears, the smell of burnt oil, as well as the change of its color from red to dark brown.
Starting to drive on an unheated automatic
During the fall period, the temperature marks are approaching zero, and sometimes fall below 0 degrees Celsius. And in such conditions not only the power unit, but also the gearbox needs warming up.
And if to start intensive loads at once it is possible to say goodbye to glands and sealing inserts completely. The optimal temperature of transmission fluid in an automatic transmission is from 50 to 90 degrees Celsius.
Usually there are no indicators in front of the driver, which alert about transmission warming up. Therefore, regardless of the circumstances, it is recommended to start driving smoothly without sudden movements and jerks.
Experienced motorists practice the method of warming up the transmission on the spot. For this purpose, they move the selector to the D position and then to R and let the box work with such settings for 1-2 minutes.
Starting with two pedals
The “win-win” method to ruin a box-automatic is as follows: in a mode Drive it is necessary to press all pedals up to a stop, and then sharply to take off the left foot from a brake. It will lead to show slips, smoke and abrupt start from a place.
However, a dynamic and abrupt start leads to quick mixing and overheating of the transmission fluid, due to which it loses its characteristics.
Transmission also overheats when slipping in mud or snow. It becomes the reason of fluid degradation and friction locks burning. Driving uphill speeds up the automatic transmission failure.
Failure to change, under or overfilling the transmission fluid
There are still hundreds of stories, when car owners don’t change oil during the years of owning a car with an automatic transmission. However, this is a colossal mistake. In severe circumstances, including constant urban driving, the change needs to be done more often. It is often necessary to do it after 30-40 thousand km of run, but there are also individual recommendations, prescribed in the regulations.
If the transmission fluid is nearing the end of its service life, the contact between frictions is disturbed, which puts automatic transmission at risk of failing. The matter is that even after replacement the new composition, possessing higher viscosity and slipperiness, trivially washes off the accumulated dirt, clogging thus the channels of hydroblocks. If the symptoms of such accidents, indicating problems with the automatic transmission, have been detected, the oil should be partially replaced to dilute the products of wear and tear with the new mixture.
Overfilling or underfilling the oil are very harmful factors, causing overheating and accelerated wear of the box. In the first case, the oil will be subject to foaming due to interaction with the moving mechanisms. Its surplus will begin to escape through the breather. In the second case a pump can try to “hobble” air, and then the liquid will start foaming. However, both in case of overfilling and underfilling the damage for automatic transmission can be enormous.
Failure to observe the rules of towing
If you start towing a car with a faulty transmission, it can lead to dire consequences up to complete failure of the power unit due to improperly working lubrication. To be sure in quality and efficiency of transmission fluid you can see its level – if it is not reduced after the engine start, the car shall be towed.
You may also make gross mistakes while towing a car with faultless automatic transmission. To exclude them, you need to put the selector in “neutral” (position N). You may also want to consult your vehicle’s owner’s manual or stick to the strategy of driving no faster than 50 km/h with an allowable towing distance of 50 km.
Frequent activation of the park mode
Some motorists, as is the case with manual transmissions, frequently put the automatic transmission selector in the P (park) position – for example, when stopping at a traffic light. They can easily be detected by the operation of the reversing lights, as the selector passes through the intermediate R value.
Such actions obviously do not render any benefit to a box, and also cause the accelerated wear of friction clutches. Also the power unit will feel worse: at sharp starts it will start to work in a stretch.
Refusal from use of a handbrake
When standing at an angle, the body physically influences the latch on the transmission shaft.
Because of this, it is better to activate the parking brake when positioned on an incline, and before the selector is moved to the “Park” position. And do not use “P” mode until the car has come to a complete stop. Otherwise there is a risk of total damage to the locking mechanism.
Going to “Neutral” mode
It is difficult to call such mistake rough, but it certainly does not bring any benefit to the automatic transmission. Constant switching to the N position at traffic lights cause a lot of disagreement among motorists.
As for the opinion of automakers, some companies do not recommend to practice long idle time with the switched on mode Drive. The power unit should not constantly run at idling speed in the forward driving position with the brake pedal depressed.