The ease of control of the automatic transmission is achieved by the complex design of this unit. Many complex and precise details create the necessary comfort and at the same time can be the reason for the failure of an expensive box. It is impossible to say for sure how long a used automatic transmission will last, but some points should be taken into account when buying.
The first thing to do when inspecting a vending used car is to pay attention to the presence of a tow bar. You should not rejoice at an unexpected option - the presence of a towing device indicates that the car was operated with a trailer, which negatively affects the service life of the automatic transmission. It's not bad if you manage to find out the history of the car: whether the box was repaired or not. Buying a car with a box after restoration is risky if you do not know anything about the quality of the repair. Further research can be divided into two parts: testing on the go and a direct inspection of the box itself.
Checking on the go
Ask the owner for permission to drive. Get behind the wheel, start the engine, and turn off the interior heater (or air conditioning). When moving off the road on a horizontal section of the road, acceleration should be carried out smoothly without jerks, with a sequential gear change from lower to higher. Transmission activation time cannot exceed 1-2 seconds. Small, weak jerks (but not shocks in any way) indicate, most likely, too high idle speeds or breakdown of engine mounts; i.e., it has nothing to do with automatic transmission. But slipping (the speed does not change, but the engine speed increases) should alert.
Then accelerate on a flat road to about 40 km / h and brake sharply. Then quickly move the selector from neutral to the "D" sector, forward, and then to the "R" position, back. The right gear should engage, and you will feel a slight push back or forward. Now you need to accelerate to 60 km / h and sharply drown the gas pedal to the floor; in the direction of travel, the gears (from 3rd to 4th) should be switched on smoothly and quickly.
Automatic transmission inspection
It is recommended to put the car in the inspection pit. But first, you can check the automatic transmission oil (the composition is called ATF). Start the engine and put the selector in the "P" sector. Then remove the dipstick from the automatic transmission, wipe it with a cloth and reinsert it into the socket. Pull it out again and wipe it with white paper; the oil trail should be slightly brownish, almost transparent, without the slightest trace of metallic inclusions. Pay attention to the smell of the oil trail - you should not feel burnt rubber or fumes in it. Under the car, inspect the automatic transmission case (walls and corners of the case); they should not have oil smudges and traces of mechanical stress. The latter say that the unit was removed for repair or replacement.
