- P - parking (parking brake);
- R - reverse (reverse);
- N - neutral;
- D - move forward.
So, start the engine, put the lever in position D - and let's go... Until you arrive at the place and turn off the engine. Car as you press the pedal "gas" will start moving, shifting gears, accelerating, stopping.
Of course, even the smartest "machine" can not "guess", which will come to your mind in a second or two. It works, as it were, with a delay: on a manual gearbox, you would have already changed gear, preparing, for example, for overtaking, and "machine" will change gear only at the moment when you press on "gas" and start overtaking. Therefore, for all "vending machines" additional functions have been introduced: the position of the selector lever and (if the transmission is electronically controlled) program switch.
Consider the purpose and functions of these additional devices using the BMW 750 as an example.
P-R-N - already clear. The next position is D. In this position of the selector lever, the on-board computer, receiving a signal from the fuel pedal position sensor and from the vehicle speed sensor, shifts gears - from the first (inferior) up to the fourth (accelerating). Engine braking on reset "gas" not happening. But what to do if it is necessary, for example, on a slippery road or on a descent?
The actions are simple - forcibly turn on the gears you need, corresponding to the positions of the selector lever 3–2–1: by dropping "gas" and shifting the lever to 3, you will feel noticeable engine braking in the range from 100 (should not be used at higher speeds) up to 40 km/h. Further, by switching to 2, you can slow down to 15–20 km / h, and by turning on 1, you will move to a complete stop. It is recommended to practice on a good free road in advance and learn how to brake the engine in order to feel the effectiveness of such actions, since they are noticeably different from what we are used to "mechanics".
The program switch has three positions: S - sport mode, E - economical, M - manual. In manual mode, the position of the selector lever corresponds to the engaged gear. Thus, you get the opportunity to operate the transmission as a semi-automatic. It is convenient when driving on a slippery road, sand, mud, etc. e. where sudden changes in force on the wheel are unacceptable.
The sport mode differs from the economic mode only in that gear changes occur at high engine speeds.
For cars of other companies, the selector lever may be designed differently, but the functions and control methods are the same. So, on modern American and Japanese cars, mode D is after neutral, which means overdrive (O.D.) and corresponds to the fourth, accelerating gear. Sometimes there are only forward positions on the selector lever (D, 2 and 1) and there is an overdrive on/off button (JEEP Grand Cherokee, LINCOLN Mark VIII, etc.). In this case, to turn off the fourth gear, it is necessary to turn the button to the position "O.D.off".
It should be noted that on many American FORD cars (Taurus, Escort, Town Car) the selector lever has positions OD, D and 1, i.e. it is impossible to force second gear, which limits the possibility of engine braking and climbing.
Owners of cars with automatic transmission must follow a few rules:
Check the oil level in the box at least twice a month.
It should be remembered that:
- the oil level is checked only with the engine running;
- the dipstick usually has marks for both cold oil and hot oil. If the label does not indicate the temperature at which the oil level should be checked, do this only on a warm box - after 10–15 km of run;
- the oil level is usually checked in the parking lot (R). The probe must have an inscription specifying the method of verification. So, on the JEEP Grand Cherokee, the oil level is checked only in neutral.
Change the oil in the box after 30,000 km of run.
It should be noted that the universal oil for automatic transmissions is Dextron. Modern oil is designated Dextron III. It can be mixed with oils of previous brands (Dextron II, IID and IIE). It has a more stable viscosity and more powerful additives that improve the performance of the box. CHRYSLER transmissions use MOPAR ATF Plus, which can be successfully replaced with Dextron III. Dextron-type oil is also used for ZF transmissions, however, on BMW 540 and 740 vehicles, only ESSO ATF LT 71141 synthetic oil is used. It is also used in all transmissions of this company that have a green company label. You can mix oils if necessary, but it is undesirable.
Tow a car with an automatic transmission no further than 30 km and at a speed of no more than 50 km/h if the engine is faulty or there is no oil in the box.
Remember that in case of emergency, you can tow the car over long distances, but you should pour an additional 2-3 liters of oil into the gearbox so that all parts literally bathe in it.
Avoid overheating the engine, as this can lead to a sharp overheating of the oil in the box and, as a result, to the failure of the box.
And the last thing: if you experience noise, vibration, hard shocks when shifting gears, long shifts, etc., immediately contact specialized centers for the repair of automatic transmissions, especially if your car has an electronically controlled transmission. Timely diagnosis will prevent significant repair costs.
Do not try to fix the problem yourself - your curiosity, self-confidence and savings on "Kulibins" will be very expensive.