How to Сheck the Automatic Transmission when Buying a Used Car

Buying a used car is a challenging task, which requires certain knowledge and a little luck. People who sell their cars rarely inform potential buyers about any issues related to the car, and in many cases they may even not know about numerous drawbacks of their cars. Thus, reliability becomes a primary issue while dealing with used cars. When buying a used car, it is recommended to invite a specialist who can perform diagnostics of the body, engine, suspension, and especially automatic transmission (one of the most expensive car components).

But what if you have no chance to examine the car with the help of professionals? In this case, potential buyers have to tackle this problem independently. In this article we will provide helpful tips on how to examine a used car equipped with an automatic transmission.

STEP1: Talk with the car owner

If you have found a used car, which looks good and has a reasonable price, then, first of all, you have to question the car owner about the following:

- Peculiarities of the car usage

- Transmission maintenance operations

- Transmission repair services

Peculiarities of the car usage

If the car under examination had many owners or it was used as a taxi or for transporting of heavy cargoes with the help of the tow bar (even its presence is a bad sign), as well as for off-the-road driving, etc., then it is better to drop the idea of buying such a car, even if all other car components are in good condition.

A detachable tow bar

By the way, if there is no tow bar, then check possible signs of its previous usage and traces of the rope on towing points – towing also has a bad impact on automatic transmissions. Cars with automatic gearboxes are not really good at dealing with extreme conditions. For example, a 15-30 minute automatic transmission slipping in snow or mud can lead to ATF overheating or automatic transmission breakdown.

Questions on transmission maintenance procedures

First of all, the car owner should tell you about all transmission maintenance procedures: information on transmission oil (ATF) changes, and whether these services were accompanied by the filter replacement. If it turns out that the car owner didn’t change ATF with filter and the car mileage reached more than 80 thousand kilometers, then you should expect automatic transmission problems in the immediate future (at the turn of 100 thousand kilometers or more), even if you instantly change transmission oil after buying this car.

According to the regulations of most automakers, ATF in automatic gearboxes should be changed before the mileage reaches 60 thousand kilometers (optimally at 35-45 thousand kilometers). If ATF change is accompanied with replacement of the filter, then it’s a positive sign. This operation should be implemented at certified service stations, which issue a cheque, and, at the best case, provide a warranty.

Therefore, it is recommended to ask for workshop orders and other evidence of gearbox maintenance procedures from the car seller. Take into account that these days many automatic gearboxes are described as “maintenance free”. Manufacturers of such transmissions claim that their products do not require ATF and filter changes, but actually they do require maintenance, and well-timed ATF change prolongs the transmission service life.

If the car owner says that he didn’t change ATF or filter, since the transmission in his car has a “lifetime” ATF, then it’s better to avoid such cars, because their automatic gearboxes usually get out of order when reaching the mileage of 120-130 thousand kilometers. Some owners of cars with so-called “maintenance free” automatic transmissions, on the contrary, may assure you that they replaced the filter every time they changed ATF. However, to replace filters in such cars (due to the lack of the pan), you have to disassemble almost the complete gearbox. Therefore, it is enough to ask several elaborative questions related to this procedure to determine if the car owner deceives you or not.

Questions on the transmission repair history

If you consider purchasing of a used car, it is hardly surprising that this car may have a repair record which includes transmission services. It is necessary to learn more information about transmission issues which occurred in this car and to find out how these problems were solved. Auto transmission repair procedures should be implemented at professional workshops which provide documents on delivered services.

However, some specialists are very pessimistic about used cars with rebuilt gearboxes and recommend not taking risks, even if the car owner provides workshop orders on repair procedures. They claim that repair procedures on automatic gearboxes fail to give desired results, since it is almost impossible to implement gearbox repair services with manufacturer’s accuracy. In many cases, the result of such repair services lasts for a few months only.

STEP2: Examination of the transmission and ATF

Visual inspection of the automatic transmission

Before inspecting the automatic transmission of a used car, it is required to warm up the car. In summer, this process may take 3-5 minutes while in winter you have to wait for 10-15 minutes. Firstly, it is necessary to place the examined car on an even surface and shift to “P” (parking) mode (in some cars (for example Mitsubishi) it is required to shift to N mode). All transmission tests should be performed after the car warm-up.

After the warm-up, it is required to open the hood, while the engine is running (with the minimum engine idle speed) and inspect the gearbox visually. The transmission should not have any oil leaks, and it should not be distinguished by the level of contamination from the rest of the powertrain section. It is also necessary to examine the transmission from the bottom side.

ATF examination

Before starting ATF examination you should take into account that there are two types of automatic transmissions:

• So-called “maintenance free” transmissions which do not have a dipstick
• Maintainable transmissions equipped with a dipstick

However, this division is conventional and, in fact, all automatic transmissions are maintainable. But some sellers of used cars, replying to the question on ATF change, resort to this gimmick and claim that ATF in their vehicles does not require any change. But you should not fall for it, otherwise you may buy a car with a faulty automatic transmission.

It is required to estimate ATF state according to the following criteria:

• Level
• Consistence
• Color
• Suspensions
• Smell

First of all, it is necessary to warm the ATF up to the running temperature, then shift to “P” mode (or in some cars to N mode), shut off the engine and start all tests. When you deal with so-called “maintenance free” transmission, then the ATF quality can be only estimated by oil smell, all other parameters can be checked at the workshop.

If the examined car has a dipstick it will be much easier to perform a profound examination. First of all, it is necessary to check the ATF level: the level on the dipstick must remain within the range from “HOT” to “COOL”, because the ATF shortage or its abundance may be harmful for the automatic transmission. The ATF in normal condition has a thick consistency – it should not come off the dipstick as water.

The next thing to do is to check ATF color – take a white rag or white sheet of paper and wipe off the dipstick. The color of ATF should vary from red to dark-red. If ATF is brown, but is also transparent and there are no suspended inclusions, then this color is also allowed – this used automatic transmission is in normal condition, but an urgent change of ATF is required. If transmission oil is dark and non-transparent or completely black, then you’d better find a different car. If you notice any suspended matters (fibers, chips, metal particles) in ATF, then it is a vivid sign of the gearbox wear-out and you should also avoid such cars.

Regardless of ATF color, it is necessary to check its smell. As is well-known, automatic gearboxes have friction discs (analog of the transmission clutch). If ATF and filter are not changed on a timely basis, the ATF will have burnt smell caused by wear-out of friction clutches. A strong smell of burning indicates that friction clutches are worn, and the gearbox will require a serious repair in a little while.

STEP3: test drive of a used car

Automatic transmission testing at idle speed

At idle speed the automatic transmission is tested as follows:

• Brake pedal is depressed;
• Gearbox selector is shifted to all operation modes (transmission gears) with an interval of 3-5 seconds – all gears should be engaged instantly (the maximum lag time is 1 second). During gear shifting you should not experience any kicks, jolts or gear engagement delays;
• Gearbox selector (while the brake pedal is depressed) is shifted to all gears, but this time without any pauses;
• With the depressed gas pedal, the driver has to perform the following gear shifting combination: Drive-Reverse-Drive. In this case, the maximum lag time must be limited to 1,5 seconds. Pay attention to hard jerks, kicks, and unusual sounds.

With properly operating used transmissions the driver may experience light and smooth jerks (most of all, they are felt when shifting to Reverse and Drive), but these jerks should not be of hard, short, and intermittent nature. Non-faulty automatic transmissions are noted for smooth and quiet operation.

Automatic transmission testing in dynamics

Before the test drive, it is desirable to choose a straight clear path where there are no possible obstacles for uninterrupted acceleration up to 100 km/h (traffic lights, jams, etc.). The driver should estimate transmission gear shifting quality while performing the following testing operations:

• Smooth start and acceleration
• Fast acceleration and braking
• Free movement with downshifting
• Testing of Overdrive function

Smooth start and acceleration

Firstly, the driver should shift from “P” to “D” mode, then smoothly accelerate the car from a standstill, and in the same smooth manner depress the gas pedal before reaching the speed of 50-60 km/h. Before reaching this speed (50-60 km/h), the fault-free automatic transmission should shift gears at least two times (from 1-st to 2-nd, and from 2-nd to 3-rd).

It is required to pay special attention to the moment of shifting from the 1-st to the 2-nd gear- at this moment the driver should not experience any hard jerks or kicks. After that, it is necessary to continue smooth acceleration up to 90 km/h. The driver has to engage all gears before reaching this speed mark. During this stage, it is required to carefully monitor any jerks and sounds while shifting gears.

The fault-free automatic transmission operates almost noiselessly (there may be light and smooth jerks while shifting gears). At the same time, it is necessary to monitor readings of the tachometer. For example, when testing the 4-speed automatic transmission at the speed of 85-95 km/h, the tachometer should show no less than 3000 revolutions per minute (RPM), while in case with the 6-speed transmission this parameter should be a little more than 2000 RPM.

Fast acceleration and braking

For fast acceleration from a standstill, it is required to shift to “D” mode and harshly hit the gas pedal (just do not overdo it). The car with a good transmission will accelerate without any problem (RPM=5000-6000). It is useful to compare the result of this test with the data of the car manufacturer: for example, if according to the car manufacturer the acceleration up to 100 km/h should take 10-12 seconds, then this test should vividly show the operational capacity of the car.

If the driver hits the gas pedal and the RPM parameter is OK, but the car itself does not produce the expected dynamics, then it indicates the automatic gearbox slipping. Consequently, the automatic gearbox in tested car will soon require repair or replacement. After testing dynamics under rapid acceleration, it is necessary reduce the speed to 40 km/h and sharply press the brake pedal to check the emergency braking – if everything works fine, then the gearbox will easily reduce the speed, and the car will stop.

Free movement with downshifting

This test is required to check the process of downshifting in the automatic gearbox of a used car. Some people think that this test is excessive, but, in fact, potential customers should perform all possible tests to be certain in reliability of the car. First of all, it is required to accelerate the car up to 90-100 km/h and release the gas pedal (start coasting). While coasting, the transmission should downshift smoothly (almost seamlessly) with corresponding changes in value of the tachometer.

Testing of Overdrive function

If the transmission system includes the overdrive gear (overdrive function – analog of the 5-th gear in the manual gearbox), then It should also be tested. To perform this test, it is required to accelerate up to 60-70 km/h and press the overdrive button (ON) – the transmission system should upshift. By switching off this function (OFF), the gearbox should downshift by one gear. If the driver sees the indicator Check Engine (when the Overdrive is engaged), then it may be a sign of the automatic transmission breakdown.

Learn more about Overdrive function in automatic transmissions

Other helpful tips

• When examining a used car, pay attention to its tires, especially when buying an SUV. If you see that the car has some off-road type tires, then it will be an extra incentive to check the gearbox more thoroughly;
• While testing the acceleration parameter, the driver should understand that cars with a low capacity engine package will more likely fail this test;
• A potential buyer of a used car should know that an electronic “brain” of the gearbox analyzes all commands from the driver on the basis of the gas pedal engagement. In other words, for the automatic gearbox it really matters how the driver depresses the gas pedal (abruptly, smoothly, as far as it will go, etc) – on the basis of this data the automatic gearbox determines the algorithm of gear shifting.

All in all, tests for estimation of the automatic gearbox condition in the field environment seem not so complicated and their implementation will show whether you still should consider buying a particular used car or find more appropriate option. However, to perform abovementioned tests drivers must have some basic knowledge on the automobile engineering, particularly about automatic transmissions and their potential problems (automatic gear shift problem (harsh shifting, delayed engagement), transmission slipping, transmission leaks). Therefore, before buying a used car, young drivers should learn the purpose, composition, and operation principles of core car components or request assistance from more experienced friends. Otherwise, there is a high probability of buying the car which will shortly require high-priced auto transmission repair.