Contemporary technique is becoming more complex, and quite often we use it without understanding how it functions. However, it is not hard to understand that wearing out of the smallest part is a way at first to slipshod work and then break-down of the whole automobile.

Unlike window deflectors or custom floor mat, an automatic speed box is a shrewd unit. It consists of plentiful precision pistons. One of them needs just to be out of work, and the transmission stops working.

The transmission oil overheat influences the work of the automatic gearbox - 20-30-minutes' time of skipping in deep snow is enough to burn the transmission down. Many working parts of the automatic transmission naturally wear out. There is a magnet in an oil pan that draws metal powder to itself. Even after 100 thousand miles it will be covered by a thick layer of a metal touch. Moreover, just some automatic gears work long after repair - they consists of too large number of precise parts, and a breakage can be caused by any slightest error or a mote.

It follows that purchasing a second-hand car the automatic transmission despite all its reliability demands especially careful attention. Otherwise you won't be able to avoid a car breakage, which leads to expensive and difficult repair.

What should draw you attention if you purchase a secondhand car with an automatic gear box?

The main thing is to check up, as far as possible, the history of the car. It will save your time and money. Pass by if you find out that the car was in a hiring service or if it were repaired after a serious accident. Find out some information about previous repairs of the transmission from the former owner or the seller. If a repair of the transmission really took place you'd rather search for another car. It's not a repair itself that matters - a car may function even much better if repair took place. But the matter is that some repair shops can't do it properly. It is impossible to define the quality of the repair. There exist another thing worth paying your attention to- it's turnbuckle presence since trailer transportation causes additional deterioration of an automatic transmission.

What are the ways of testing the condition of the automatic transmission?

Let's start with the check of oil level and its condition.

The engine functions with idle wheel, the automatic gear box is switched in «Park» position. The oil level dipstick should be pulled out and wiped with the help of a clean dry rag. Put it back and then again take it out. Consider the oil attentively. Using paper wipe the oil level dipstick. The spots on a piece of paper ought to be clean and limpid, they shouldn't have any alien particles or any metal traces. If oil is new it's of a red color. With time it can get a brownish tint, but not black. Try to smell it as well. There mustn't be a smell of burning.

To make a conclusion, in case the oil is dark, in case it is full of metal particles or if the oil smells with something burnt it is better not to buy such a car.

However, a lot of up-to-date automobiles have no oil gage, and there's no other way to check oil rather than to turn to specialists in some technical center. The only way to test the transmission in such a case is to check a car in practice on the road.

How can it be done?

As the car is not yours yet, be on the alert.

The badly functioning transmission can be determined first of all by a delay between the drive choice D (Drive) or R (Reverse) and gear shift.

Warm up the car a little with the transmission in position P (parking) unless turns fall to 650-850 a minute.

Your foot being put on the brake, you shift a gear to D (Drive). If the car chose the mode correctly it would start to drag forward. The process of a gear change should be soft, without pushes and knocks.

When you switch to N (Neutral), the disconnection of the gear should take place.

The next step to do is to switch to R (Reverse). The result should be immediate - the gear should switch on, and you will feel that the car wishes to creep back. In this case there should be neither pushes nor knocks either.

Then having your foot on the break pedal, you should switch from D to R and back. No jerks, no noise should be felt and heard over and over again. In case of a delay at gear switching, it means wearing out of the transmission or its need for repair.

Let's take a ride...

Having transmission lever in position D, put your foot away the break pedal and speed up smoothly.

Up to the speed of 35-45 mph the transmission should be switched over at least twice (from the first to the second, from the second to the third). No jerks, no noise should be felt and heard in the process of switching.

The gearshift moment is defined by an easy change of a noise level of the engine and by turns falling.. If the transmission is worn out excessively, the gear is shifted with a jerk or a hold-up and maybe even with a loud noise (the most troublesome is switching from the first drive to the second).

When the speed is 20-30 mile per hour, you should press the gas up to the stop, a completely faultless automatic car will shift to low gear and turns will rise.

Then check up overdrive (if there is any). It is the button to the left of the automatic transmission lever in Japanese and American cars.

Driving at the speed of 35-45 mile per hour on an even road it's necessary to shift to the automatic mode ON with the help of the button "Overdrive". The automatic gear box should be shifted to a higher drive. Logically, when you switch the position OFF, the gear will change to low drive. There's one more problem concerning the automatic gear box - it's gear spin-out. It happens when you press a gas, turns rise, the speed rests the same.

If there is at least one of these flaws it's enough to deny buying a car. Don't be in a hurry to finish a test lap. Sometimes it happens that flaws of the automatic gear box can be observed only after warming-up of the car or on the contrary - they will disappear after warming up. The time spent on such a meticulous check will turn back with smaller problems in future. No matter what temperature oil is and at what speed you are driving well functioning transmission never twitch, slip or drag. If you are being assured that various deviations like rattles, knocks and jerks are usual phenomena for the given model of the car you'd better refuse to buy this car. When during a driving test you notice a blinking overdrive «check engine», discuss this problem with the reliable expert whom you trust completely.