Before buying a car with mileage, you need to carefully check that all its parts and components, starting with the body and the passenger compartment, and ending with the engine and gearbox, are in good condition. If you prefer a vehicle with an automatic transmission, then when checking it, you need to pay special attention, since the device is "capricious" and expensive. When an automatic transmission breaks, not every mechanic will even undertake to repair such a complex device, it is easier to repair several manual transmissions than one automatic box. Even after a high-quality diagnosis, its work remains in question, because it is already impossible to achieve a similar standard assembly. The slightest grain of sand or chips that have fallen into detail, can cause a repeated system failure.

Buying a car

Automatic transmission is like a weak link of a car, on the one hand, it is reliable in use, on the other hand, its design is complicated, it requires proper maintenance and delicate handling. With good operation without skidding in snow and mud, the automatic transmission can serve for more than one decade. But getting a car with it is not guaranteed that the previous owner did not overheat this node. All automatic transmission malfunctions are due to overheating, so before you buy a car with such a transmission you need a detailed check. Many drivers, knowing the complexity, prefer to abandon the supported automaton by acquiring mechanics, because all of its testing comes down to the banal test of smooth shifting, checking the oil and listening to noise.

Content

• 1 Check box automatic
• 2 Visual inspection of the automatic transmission
• 3 Test race
• 4 Hydrotransformer AKPP
• 5 The state of the adjusting cable solenoids

Check box automatic

Если вы ничего не понимаете в устройстве, то для объективной оценки состояния транспортного средства рационально будет воспользоваться услугами профессионала. If there is представления о системе, то начать проверку нужно с уточнения информации об автомобиле и его прежних хозяевах. Когда машина приобретается не у дилера, а у хозяина, то рекомендуется задать вопросы:

1. About the conditions in which the car was used. Pay attention to the particular use of the vehicle. When the car owners had several or often traveled there, used as a taxi, etc., then it would be better to refuse and consider the following options, exploited, not so aggressively. Vehicles with automatic transmission do not go for extreme use, so the slightest slip causes great damage to the system. Therefore, see if there is no tow bar, then there may be traces of its attachment or cable on the towing eyes.

   

   Automatic transmission

2. Have there been technical maintenance of automatic transmission. Check if the oil has been replaced in the transmission. When there was no replacement, and mileage over 80 thousand km, then soon to reach 100 thousand km there will be problems with the box. This result will happen even if you immediately change the oil after the purchase. According to the regulations of most automakers, the oil should be changed at the turn to 60 thousand km, that is, on average, with a mileage of 35-45 thousand km. If the seller replies that the oil has changed before, then it is important to find out who changed it, when and for which mileage, and whether the filter changed along the way. Replacement should only professionals from the service, because in some machines with on-board computer, before changing the oil, you must connect to the "brain" of the vehicle. In addition, after servicing, a work order, a check and sometimes a guarantee are issued to the service station. The old oil must be replaced with the transmission ATF (Automatic Transmission Fluid), which contains a special compound for the machine. If, according to the rules, the filter was changed along with the oil, this would be only a plus for the purchase.
3. On the repairs carried out automatic transmission. When the repair was, it is better not to waste time and abandon the car, even if all the documentation is in order and there is an extract for repairs. With an automatic box it is better not to risk, in any case, there will be problems and additional costs for permanent repairs. Another thing, if the gearbox was simply replaced and this is confirmed by a certificate from the center. This is not bad, but it is better to ask what led to such drastic measures. While talking about the gearbox, watch the reaction of the seller, because if you feel anxiety or confusion in the information, then you lie. When the reaction did not bother you boldly proceed to the next stage of the inspection.

   

   Check oil dipstick

Visual inspection of the automatic transmission

Check the automatic transmission when buying просто, если знать, что именно проверять. Так как состояние автоматической трансмиссии сильно зависит от температуры типа и качества масла, то начинать осмотр нужно с этого. Осмотр системы происходит только днем при сухой погоде. Сначала осмотрите пространство под капотом, на коробке не должно быть подтеков и грязи. Можно даже визуально проверить коробку со стороны днища. Далее, переходим к проверке масла, здесь нет ничего сложного:

1. The selector is set to «Park».
2. The engine start at idle and give a little work.
3. Silenced the engine and pull the probe out of the transmission, wipe it with a napkin and dip it back into the tank.
4. After again, they take out and wipe the oil from the dipstick with plain paper.
5. The oil should have a thick consistency, in color it should be red or brown, not have a burning smell. When the light of the liquid is black and there is a burning smell, there are also malfunctions in the operation of the automatic transmission.
6. Also see if there are otherworldly particles and dirt in the oil layer. If there are no metal flakes, everything is in order.
7. They also check the oil level: on the dipstick, it should be within the HOT marks if the box is warm and between the COOL marks and the car is cold.

Automatic check in dynamics

There are models of gearboxes without a dipstick, so it is simply impossible to check the condition of the oil on your own. In this case, as an answer to the question: how to check the box for automatic operation when buying a car - only a test drive remains. Everything else needs to be entrusted to the center for car maintenance.

Test run

The sequence of actions in which the automatic transmission should respond instantly. First we check the device at idle:

1. Start the engine.
2. Transmission set to mode «Parking», warm up the car a little.
3. Reaching 650 rpm, squeeze the brake and switch the selector mode «Drive». The machine should begin to sway forward.
4. We return again to the mode N (Neutral) - the box itself should turn off.
5. Next, again press on the brake and turn on the mode «Reverse» –Transmission should work without delay. There will be a feeling that the vehicle is going backwards.
6. Now go to mode D.

If there is a delay of a few seconds during mode switching, it means that the automatic transmission is faulty somewhere and needs to be repaired or replaced.

Automatic check on the service station

The next step of the check is a check, it should be carried out as thoroughly as possible, paying attention to all the details. Before the test drive, it is advisable to choose a straight section of the road, without obstacles (traffic police posts, traffic lights, etc.) so that you can carry out continuous acceleration to 100 km / h Sequence check automatic transmission dynamics:

1. We put the selector in mode «Drive»release the brake.
2. While the speedometer is typing 60 km / h, the box should switch at least twice to second and third gear. Noise and switching should be felt, only slightly, no system delays, especially no jerks should arise.
3. When the speed reaches 50 km / h, you can squeeze the gas all the way. When the automatic transmission in good condition will switch to a lower gear, and the engine speed will increase. When there is a delay, it indicates wear.
4. In addition, look for the indications of the tachometer. That is, with a 4-speed box and a speed of 85–95 km / h, it should produce at least 3,000 rpm, and at a 6-speed gearbox it is slightly more than 2,000 rpm.
5. Now check out the sharp start. Set the mode “Drive” and sharply press the gas pedal. The machine should instantly gain momentum of up to 5-6 thousand. Here, the dynamics should be compared with the manufacturer’s stated figures, they should be the same or slightly different.
6. If there is «Overdrive»then acceleration is gained up to 70 km / h and we include the position ON –Transmission should be upgraded. When turn off the position OFF, Automatic transmission will return to downshift. If during the overdrive test the position ”check engine” need a professional inspection.

   

   Transmission Check

7. It also means an automatic transmission breakdown, maybe even slippage while pressing on the gas while the revolutions are increasing. We draw conclusions: there should be no noise in the operation of the machine, even if the seller says that for this model of car this is the norm.

Hydrotransformer AKPP

An equally important part when checking the automatic transmission is the torque converter. It represents a tightly welded knot, similar in shape to a bagel. His task is to transfer the rotational element from the engine to the automatic transmission, using two turbines rotating in oil. Control, for it and its optimization with the checkpoint is carried out using a computer control unit. If there are any problems in the system, the automatic system gives an error signal or completely blocks the engine when the automatic transmission mode changes. It is difficult to determine the breakdown of the torque converter at a mechanical level, by diagnostics, for this you need to disassemble the system and inspect it. You can only check the automatic transmission torque converter by external signs:

• if plastic smells come from the box;
• when there is metal dust on the dipstick, this indicates a malfunction of the end washer and the torque converter;
• if at a speed of 60 to 90 km / h vibration is felt, which only increases. The reason is oil, which clogged up particles of debris oil filter;
• if during the shift there are mechanical noises, leaving with an increase in revolutions. Usually the problem lies in the thrust bearings;
• the presence of a metallic knock when shifting gears;
• if the overrunning clutch is not in order, then this is reflected in the vehicle dynamics.

  

  Checking the adjusting cable solenoids

The state of the adjusting cable solenoids

While checking the automatic transmission, it is important to assess the condition of the cable that controls the throttle valve. This element of the system may wear out, and then the transmission starts to work incorrectly. In addition, the possible weakening of the cable, it is possible to determine if the automatic transmission includes reduced or increased speed is not when you need it. Loose cable leads to overheating of the box and increased fuel consumption. The cable must not only be tensioned, but also lubricated. The solenoid automatic transmission is a mechanical regulator valve that opens and closes the channel in the hydraulic system at a signal from the control unit for the passage of oil flow. The automatic transmission solenoids can be checked only with the use of diagnostic equipment. Best of all, to make it a specialist in the service station.