About automatic transmission, FAQ, which spoils the automatic transmission and other useful information ...
Incision eight-speed automatic transmission ZF 8HP70.
Automatic gearbox (automatic transmission, there is automatic transmission, "Automatic gearbox (gear shift)") is a kind of transmission of cars, which provides automatic (without the direct participation of the driver) selection of the gear ratio corresponding to the current traffic conditions, depending on many factors.
Automatic transmission - how does it work?
The share of AKP in sales of best-selling models.
I advise everyone to read the automatic transmission, there are many useful things ...
Continuous use of the sport mode of the automatic transmission does not hurt, rather it will hurt your pocket (fuel consumption increases to 30%).
Some aspects of the AKP
1. Sport mode as such during normal driving does not lead to any particular wear on both the box and the engine.
2. The car accelerates from 0 to 200, for example, equally quickly regardless of whether the so-called Sport mode or not.
3. Fuel consumption, oddly enough, very little depends on whether in 3rd gear to go with speed. 100 km / h or on the 4th.
4. Ruining the box is not "sportmode", and:
b) switching, when the "gas to the floor"
c) Switching down when speed is high
d) Low or high level of oil
d) Sharp ride on the overheated box
e) Driving on "borderline" modes between gears on the boxes, where the "hysteresis" is small
g) Riding with very frequent gear changes
g) "gasping" with the gas pedal (Among the "professional drivers" who have been driving carburetors all their life, there is a bad habit - when starting off, gas is not exactly thrown, but pulsed, 4-7 times per second by adding and releasing gas. they do it before overtaking, for example. Why this is a separate conversation, but this does not affect positively the automatic transmission.
In all hydromechanical automatic transmissions there is a strong dependence of the number of the gear not only on the speed, and on the engine speed, but also on the position of the "gas" pedal. Therefore, when changing the position of the pedal at constant speed and speed, if the difference in the coordinates of the pedal exceeds the hysteresis set by the designers
when designing the box, the box is switched up-down-up ... Of the latest models, the behavior of the Mersa-goggles of a small displacement is noted for such behavior)
h) "gas supply" during the switch "up"
i) a sharp "gas discharge" at the moment of switching "down"
d) a constant ride with "slip"
k) reverse gear at a speed of more than + 1-2 km / h
l) the inclusion of the front modes at a speed of more [minus1-2] km / h
m) switching front / rear with increased engine speed (> 1000-1200 depending on the type of box)
m) riding a box that is not at all warm at any temperature (The meaning of "warming up" even at +25 is not warming up itself, but:
- 1. Pumping oil to remove bubbles from areas where they should not be.
- 2. Washout of unwanted harmful particles of any kind from friction pairs, which were "stuck" there from the previous trip, and the pressure of the heated oil was not enough to "flush" them.
- 3. Pumping oil to drastically reduce its viscosity to working. Oil at the same temperature has a different viscosity depending on the "history". Well, like sour cream, only a smaller effect - when it lasts a few hours - it thickens a lot. Stir - again liquid.)
o) towing a car with automatic transmission over long distances
p) towing a car with automatic transmission at high speed
p) simultaneous use of the "gas" pedals and brakes
c) automatic transmission operation in tandem with the “three way” engine
r) operation of automatic transmission paired with "crunchy" CV joints
s) frequent starting on higher gears (on the boxes, which in principle allow it)
f) long ride on automatic transmissions that are in “protected modes”
x) further driving on an apparently defective box
c) when starting the gas supply, BEFORE the car received a significant push forward as a result of switching on the transmission
h) "pushing" switching by adding gas pedal
w) riding on poor quality old oil
y) driving with frequent locking / unlocking of hydrotrans (on automatic transmission, where it is)
b) riding on oil that does not correspond to the manual (dexron instead of dexron-II, for example)
s) an abrupt gas supply after engine braking with the low gear engaged
b) riding with an overheated motor
e) a sharp ride on a newly renovated automatic transmission
u) fast sharp ride backwards
i) driving about business, when you need to go to the service.
Frequently asked questions about automatic transmission
1. How to check the oil level in the automatic transmission?
For most cars, the oil level (ATF) in the automatic gearbox (automatic transmission) is checked when the engine is running and the range selector lever (RVD) is set to "P". On the dipstick for measuring the oil in the automatic transmission, as a rule, there are several marks. The top two, and sometimes the only ones, correspond to the normal level of oil heated to operating temperature (90 ° C). Often this area of the probe is marked with a notch and / or the inscription "Hot". In order for the oil in the automatic transmission to warm up to the working temperature, it is necessary to drive 15-20 kilometers. After warming up the oil in the automatic transmission, place the car on a flat, horizontal platform. Pull the dipstick out of the automatic transmission, and wipe it dry. Then insert the probe back into the probe tube until it stops and remove it again. The lowest dry place on the dipstick and will correspond to the level of oil in the automatic transmission. Sometimes there are also lower marks on the dipstick corresponding to the level of the cold one. This label is intended for approximate determination of the amount of filled oil in case of its replacement. Finally, the level should still be checked after the oil is warming up. Often it is written on the dipstick, in which position of the RVD the level and type of oil used should be checked. There is a special case - Honda and Acura cars. Their oil level is checked also after reaching the oil temperature of the operating temperature, but with the engine shut off. There are automatic transmissions in which the oil level is checked when the RVD is set to the "N" position. Such gearboxes are used on Mitsubishi, Proton and Hyundai front wheel drive cars. Note that this is not about car models, but about transmission models. For example, front-wheel drive boxes and Mitsubishi can be found on Chrysler cars and vice versa. If you have a car Proton or Hyundai, then the oil level in the automatic transmission should be checked in the RVD "N" position. In the case of a Mitsubishi or Chrysler car with a transverse engine, look at the automatic transmission from the side of the wheel. If there is a stamped side cover fixed with ten bolts, then you have an automatic transmission manufactured by Chrysler, and the oil level should be checked when the hydraulic hoses are set to the "P" position. The absence of such a cover indicates that the Mitsubishi automatic transmission is installed on your car, and the oil level should be checked when installing the WFD in the "N" position. Also in the "N" position of the RVD, the level is checked on Jeep Cherokee and Jeep Grand Cherokee cars with automatic transmissions manufactured by Chrysler. But on some models of these cars are installed automatic transmission company Aisin Warner, in which the oil level should be checked in the RVD position "P". To determine the type of box installed on your car, you can use the following method. The Aisin Warner automatic transmission has a rectangular pan, the probe tube is welded directly to the side pan, and there is a drain plug in the back of the pan. In Chrysler automatic boxes, the pallet is almost square, the probe tube is installed in the crankcase and there is no drain plug. In addition, checking the oil level in the automatic transmission cars VW, Audi with three-speed boxes should be carried out when setting the RVD to the "N" position. In some automatic transmissions, instead of a probe, there is a control plug in the crankcase. Not the convenience of this is that to check the oil you need to put the car on the "pit" or lift on a lift. But there is an advantage: never pour oil in the automatic transmission, which is very important. Such traffic jams have automatic transmissions of ZF, which, as a rule, are equipped with BMW cars. And on the BMW with five-speed boxes, the same tube serves to fill the oil. For security purposes, the level control in this case is carried out with a slightly warm oil. This is European fashion. On the “Americans”, this level checking procedure was met only in the 4T40E automatic transmission. It should be noted that there is an automatic transmission, which, in general, does not provide any devices for determining the level of oil. This is a Mercedes 722.6 transmission, which is installed now, practically, on all the cars of this company. The fact is that the tank, where oil is poured for automatic transmission, is connected to the oil pan through a bypass valve, the purpose of which is to maintain the required level of oil in the pan. Therefore, the level of the filled oil does not play such a value as for other transmissions.
2. How dangerous underestimated or excessive oil level in the automatic transmission?
A too low ATF level is dangerous because the pump, along with the oil, begins to trap air. The result is an air-oil "emulsion", which is well compressed and has a low heat capacity and thermal conductivity. The oil loses the most important of its properties and becomes compressible. The result will be a decrease in pressure in the control system, poor heat removal from the automatic transmission, deterioration of lubrication of rubbing elements. Operating a car with foamed oil in an automatic transmission will quickly disable the box. I would like to note that you should not confuse individual large air bubbles in the oil on the dipstick (which sometimes happens) with foaming oil, which is a uniformly foamed liquid with very small air bubbles. Foaming oil increases its volume, so when checking the level it will be overstated. In this case, turn off the engine and allow the oil to settle for some time, and then, without starting the engine, check the oil level. If the dipstick is completely dry, then you can safely add a liter, or even two. Oil can foam and rotating parts automatic transmission, if the level exceeds the permissible value. In this case, the rotating parts of the automatic transmission begin to dip into the oil and foam it. Foaming does not occur immediately after the engine is started, as in the case of a lowered level, but during movement, especially with high engine speeds. As in the case of low oil level, and in the case of an overestimated level, foaming of the oil leads to an increase in its volume, and, as a consequence of this, to its release through the gearbox breather. Peering under the car, you can often see there that the whole box is in oil.
Here is a case from practice. Ford Explorer came to the diagnosis with the complaint that something incomprehensible was happening with the level. Level - that is, it is not, and automatic transmission all in oil. In a conversation with a client, it turned out that the probe was lost and replaced with a new VIN-ordered dealer. When comparing the probe and the probe tube it turned out that the probe is much shorter than the tube. The ATF level was just at the level of the box axis. (Usually the level is approximately flush with the gasket pallet). Thus, the customer complaint was caused by too high a level of ATF in the automatic transmission.
3. The level is normal, but ATF is foaming, what is the reason?
This is possible in case of damage to the seal of the filter or the filter itself.
4. The level is constantly decreasing, and there are no traces of oil leakage.
A prerequisite for such a malfunction is the presence of a vacuum modulator in some types of automatic transmissions - a special device that generates pressure that is proportional to the degree of vacuum in the engine intake manifold. Externally, the vacuum modulator resembles a similar device on the Zhiguli distributor. The modulator is connected to the intake manifold through a tube, through which, in case of a malfunction of the modulator membrane, the oil from the automatic transmission enters the collector and burns. Typical representatives of cars on which the automatic transmission is installed with a modulator: Ford Scorpio, Ford Sierra, Ford Explorer, Mercedes, front-wheel drive cars of the concern General Motors with a four-speed automatic transmission. It should be noted that since the beginning of the 90s, the use of modulators has been abandoned and replaced with electrical sensors. Another reason for the decrease in the level of ATF in the automatic transmission in the absence of a leak may be a violation of the integrity of the cooling system. In many cars, the radiator for cooling the automatic transmission oil is built into the engine antifreeze cooling radiator. At violation of tightness of the built-in radiator, oil gets to the engine cooling system as a result of which the antifreeze turns into a pinkish emulsion.
5. How much oil should I pour into the automatic transmission?
Depending on the type, the automatic transmission can hold from 4.2 liters (DAIHATSU TERIOS) to 15.5 liters ATF (FORD EXPEDITION). It must be borne in mind that when replacing, not all the volume of oil is drained. Part of the oil remains in the control system channels, and, in addition, not all transformers have plugs for draining oil from them. Therefore, when draining the oil, some of it remains in the automatic transmission, but this is considered permissible. If you want to completely change the oil, then two or three times oil change is necessary.
6. How to determine what is poured in the automatic transmission, and what oil to fill when replacing it?
Gear oils differ in both color and smell. There are light yellow oils, and there are red hues (from light CASTROL to saturated red ELF). It should immediately be said that the color of the oil is determined only by the dye that is added to it, so that you can distinguish the oil for automatic transmission from other oils used in the car. Nothing else determines the color of the oil. In addition, after a short period of time, any oil becomes transparent brown in color. Considering that when changing an oil, not all of its volume is updated, and also that during operation, the color and smell of oil change - it is practically impossible to determine its brand, even if it has changed recently. At least one time is necessary, and a double oil change is better (in the absence of serious problems in the operation of the automatic transmission). It is necessary to use that oil which is stipulated in the maintenance instruction of the car. It happens that the type of recommended oil is also indicated on the dipstick. In addition, oil producers produce posters and albums (they can be found in specialized stores) with a list of car brands and recommended oils, both motor and transmission. Usually, the instruction manual recommends using a specific type of oil. Probably, this is not only a technical, but also a commercial justification. For example, Chrysler and front-wheel drive Mitsubishi (Hyundai) use Mopar ATF 7176, and the instructions state that this oil has enhanced frictional properties compared to Dexron or Mercon. But on the probe at Dodge RAM and Jeep Grand Chrokee can be found recommendations to flood Mopar ATF 7176 or Dexron II. So all the same it is possible. Another example: Mobil does not recommend mixing different types of oils, even its own production. And here is a quote from the bottle of Mobil Synthetic ATF: "Compatible with conventional ATF fluids" (Compatible with conventional oils for automatic transmissions). If it comes to changing the oil in the engine - the algorithm is simple. We are going to a solid store, we choose an oil manufacturer (according to one known criterion). From the entire range, choose oil for gasoline or diesel engines, choose the oil class according to API (so as not lower than in the instruction manual) and the desired SAE viscosity. Everything. Why, when it comes to transmission, do we start looking for green oil without wasting time and money? Is it because of the fact that the automatic transmission is more exotic unit than the engine? The experience of repairing several thousand automatic transmissions indicates that the causes of breakdowns are more prosaic than the mixing of various types of oils during its replacement. Of paramount importance are the operating conditions of the transmission, and even the most expensive synthetics will not help if they are violated.
7. How often should I change the oil in the automatic transmission?
The oil replacement period depends on the type of automatic transmission, and, usually, under normal operating conditions, it is recommended to change it after 70 thousand kilometers of car run (or after 2 years), and after 25 thousand kilometers (or after 1 year), if the operating conditions are different from normal (hot climate, cold climate, operation in a megacity, continuous operation of the machine with a full load, etc.). In some expensive models (for example, BMW 750) according to the instructions, an oil change is not provided at all. But regardless of anything regularly (once a week) check the quality of the oil in the automatic transmission of your car. It is necessary to adhere to the established replacement periods if during operation there is no significant change in the quality of the oil or you did not get into difficult driving conditions (stuck, towed another car for a long time, etc.). In case of darkening of the oil and or the acquisition of a burnt smell, it is necessary to replace it without waiting for the planned replacement period. But not always replacing burnt oil can save the day. Most often in these cases, overhaul of the automatic transmission is required. When changing the oil in the automatic transmission, you must also change the gasket pan and filter. In some types of automatic transmission filter replacement during the oil change is not provided, because the filter is not available without removing and disassembling the automatic transmission (for example, Daewoo Espero, Nissan Maxima (with the RE4F02A box), SAAB 900 and 95, Volvo 850, Opel front-wheel drive models with four-speed automatic transmission). How to evaluate the quality of oil in the automatic transmission? Different types of oils differ in both color and smell. If your box has recently been in repair, remove the dipstick and remember the color and smell of ATF. If during the operation the color or smell has changed a lot, then there is a reason to contact the service to check the status of the automatic transmission. When buying a car with an "automatic", the oil should be transparent and not have a dark brown shade or a burnt smell. Put the oil from the dipstick on a white paper napkin and make sure that the oil is easily absorbed, and there are no foreign inclusions. If in a faulty automatic transmission, oil was changed several times in a row before selling it, all the same, with careful analysis of a drop of oil in it, small black particles can be discerned that are not in harmony with clear and bright oil. Often, you can see a black patina on the dipstick. In this case, wipe the dipstick well and re-analyze the condition of the oil. If the raid did not reappear, then the previous one was due to the fact that the probe was not used for a long time. It also does not hurt to look into the engine cooling system and make sure that the antifreeze is transparent and does not contain a water-oil emulsion. Keep in mind that you can find red antifreeze, at first glance reminiscent of automatic transmission oil.
8. What oils are used in automatic transmission besides oil for automatic transmissions?
In the front-wheel-drive automatic transmissions, as well as in some all-wheel-drive transmissions (for example, AUDI, SUBARU), the main gear and differential are located in the same housing with the gearbox. This arrangement is called transaxle, as opposed to transmission, when the main gear is in the rear axle. If the main pair is in the same housing with automatic transmission and is a hypoid gear, then oil for hypoid gears (separate lubrication) is poured into the differential crankcase. In other cases, the lubricant can be both separate and joint. In the case of a cylindrical, helical gearing in the main gear for its lubrication is usually used oil for automatic transmission. Checking the oil level in the differential with joint lubrication is not required. In the case of separate lubrication, as a rule, there is a control plug or probe. How to change the oil in the automatic transmission? The sequence of actions for changing the oil is the same as for changing the oil in the engine. Drain the old oil, change the filter, pour the new oil. In most cases, replacing the filter requires removing the pallet. Sometimes the filter is inside the automatic transmission and is unavailable without dismantling and disassembling the automatic transmission. In this case, the oil change occurs without changing the filter. Together with the filter and changing the lining of the pallet. Usually the filter and gasket are sold in one set (Filter kit). On some models, the pallet is placed without a gasket on the sealant. If the filter is made in the form of a fine metal mesh and is not damaged, then you can leave the old one by rinsing and blowing it out with compressed air. Before installing the filter in place, check the quality of the seal of its bore. Tighten the bolts of the filter and the pallet should be strictly defined moments specified in the instruction manual of the car. After you have filled in fresh oil, it is necessary to start the engine. Holding the car brake, move the RVD in all positions, lingering in each for a few seconds. Then set it to "P" or "N", check the oil level and bring it to the mark corresponding to the cold state of the oil. Finally check the level only after a run of 15-20 kilometers, when the oil temperature reaches the operating value. In the process of changing the oil, you should assess the presence of wear products in the pan, on the magnets of the pan and in the filter. A small amount of suspended matter in oil, non-ferrous metal dust and a small gray deposit on the magnets can be considered the norm. Pieces of plastics, metals, the presence of black flakes or clay-like sediments in the pan indicate the need for an overhaul of the automatic transmission, even if there are no complaints about the work of the transmission.
Modern oils already have in their composition all the necessary additives. This question is often asked when problems arise in the operation of an automatic transmission. In most cases, problems in the work of the automatic transmission are accompanied by increased wear of the friction controls. This is an irreversible process and neither oil change nor additives will restore them. Therefore, by and large, the overhaul is the only way to restore the performance of the transmission.
10. What do the symbols of the position of the lever of the range selection mean and why are they needed?
The range selection lever (RVD) of the gearbox has several positions that have an alphabetic and numerical designation. The number of these provisions in different models of cars is different, but on all cars RVD necessarily has the provisions indicated by the letters "P", "R" and "N". Position "P" It is selected when the car is parked for a long time. In this position of the RVD in the automatic transmission, all the controls are turned off, and its output shaft is blocked, so the car’s movement is impossible. In this mode, the engine is allowed to start. Position "R Backing. Switching the lever to the" R "position while driving may result in damage to the gearbox and other elements of the transmission. In this position of the high-pressure valve, the engine cannot be started. Position" N " or only one is turned on. The output shaft locking mechanism is turned off, that is, the car can move freely. In this mode, the engine is allowed to start. For vehicles equipped with four-speed gearboxes, the high-pressure hoses have, as a rule, four e forward movement positions: "D", "3", "2" and "1" ("L"). It should be noted that in case of installation of the high-pressure hoses in one of these positions the engine cannot be started. Range "D" is the main mode Movement. It provides automatic switching from first to fourth gear. In normal driving conditions it is recommended to use it. Range "3" - you can move in the first three gears. It is recommended to use when driving on a hilly road or in conditions of frequent stops. The range of "2" - you can move only on the first and second gears. It is recommended to use on winding mountain roads. Switching to the third and fourth gear is prohibited. The range of "1" - you can move only in first gear. This range allows you to maximize the engine braking. It is recommended when driving on steep descents. On some car models, permission to use the fourth, up, transmission is carried out using a special button "OD". If it is in the recessed state and the WFD is set to the "D" position, then upshift is possible. Otherwise, the inclusion of the fourth overdrive is prohibited. The state of the control system in this case is reflected by the indicator "O / D OFF". If the use of an overdrive is enabled, the indicator does not light, and it turns on when it is disabled.
11. What are additional buttons (switches) for? What is winter mode?
On most modern cars with automatic transmission, the control system has several options for controlling gear shifting. These include - economical, sports, winter, etc. Economical program. The program is configured to provide traffic with minimal fuel consumption. The movement of the car in this case is smooth, calm. Sport program. This program is configured to maximize engine power. The car in this case develops, in comparison with the economical program, significantly greater accelerations. To implement an economical or sports program, a special button or a switch is located on the dashboard or next to the range selector lever, which, depending on the car brand, may have the designation "POWER", "S", "SPORT", "AUTO", "A / T MODE "etc. Electronic control units of almost all modern cars have a special program of starting off on a slippery road (winter program). To activate it, there is also a special button or switch, which may have the designations "WINTER", "W", "HOLD", "*", etc. In the case of its action, various algorithms of automatic transmission operation are possible, but, as a rule, in all cases the starting is carried out either from the second or third gear.
12. What is overdrive? Which mode is preferable in urban driving or overdrive?
Overdrive in the terminology of American automakers means overdrive. Indicated, usually, as "OD", or D, or D in a circle. Upgrades are recommended for measured, economical driving on the highway.
13. Is it possible to switch the range selector on the go?
It is possible, but not in all positions. It is strictly forbidden to move the RVD to the "P" and "R" positions when moving forward. In both these positions, the lever can be transferred only when the vehicle is completely stopped. Violation of this rule can lead to serious damage to the automatic transmission. In addition, it is not recommended to move the RVD to the "N" position while driving, since in this case the connection between the wheels and the engine is lost and sudden braking may cause the vehicle to skid. And in all other provisions of the RVD, you can safely translate. In some cases, it is even recommended to do it on purpose. So the translation of the RVD from the position "3" to the position "2" will increase the efficiency of engine braking, etc.
14. Should the range selector be turned "N" when stopping at a traffic light?
It makes sense only at long stops in street traffic in hot weather, to reduce heat generation and prevent the box from overheating. In other cases, this is not even recommended.
15. Do I need to use the parking brake in the parking lot if the range selector lever is in the “P” position?
For reliable fixation of the car in the parking lot on relatively flat areas of a working mechanism for locking the output shaft of the automatic transmission is enough. But if the car is on a slope, the inclusion of the handbrake is necessary. And first you need to tighten the handbrake and only then set the RVD to the "P" position. In this case, you release from the additional load associated with the desire of the car to slide down the automatic output shaft locking mechanism.
16. How to determine the number of gears in the automatic transmission?
In Japanese cars, the four-speed automatic transmission can be identified by an additional button on the high-pressure hoses, which is marked "OD OFF" or "Hold". If there is no such button, then, most likely, a three-speed automatic transmission without an overdrive. In European cars, the three-speed automatic transmission range selector lever is marked with PRND21 symbols. Four speeds - PRND3. Five-speed - PRND4? In American cars, the presence of the fourth (sometimes fifth) overdrive is indicated by the D in a circle. Having some experience, it is possible to determine the number of gears in practice, following the tachometer needle during vehicle acceleration. Each switch will be accompanied by some decrease in engine speed. Only in this case, it must be borne in mind that the tachometer needle reacts in the same way to the blocking of the torque converter (although the fall in revolutions in this case will not be as noticeable as during gear changes).
17. Is it possible to slip on a car with automatic transmission?
Nothing criminal during slipping in the automatic transmission does not occur. Increased heat dissipation in the torque converter in this case can be critical if the cooling system has low efficiency (automatic transmission cooling radiator is clogged with wear products).
18. How to tow a car with automatic transmission?
In this question, too, there is no single answer. For some cars there are very strict passport restrictions. For example, Jeep Grand Cherokee is recommended to be transported only by tow truck. Chrysler’s front wheel drive is a bit simpler. Cars with a three-speed automatic transmission can be towed at a speed of 40 km / h to a distance of 25 km, and from a four-speed automatic transmission - at a speed of 72 km / h to a distance of 160 km. And yet, whatever the car, in the event of a faulty transmission, a tow truck is preferable. The fact is that in automatic transmission lubrication is enforced, i.e. Oil is applied to each friction pair under pressure. If the transmission is faulty, then there is no certainty about the availability of lubricant. True, indirectly, the efficiency of the pump can be assessed. It is necessary to compare the oil level when the engine is off and running. If the level does not change, do not even think about towing. Towage is carried out with the engine running and the installation of the RVD in the "N" position. There is another way to tow a car with a failed automatic transmission. Pour the maximum in the automatic transmission oil, which will provide at least some lubrication of all its parts.
19. Is towing a trailer equipped with an automatic transmission?
Allowed But we must remember that the higher the load, the greater the heat release in the hydrotransformer. If you are constantly using a trailer, consider installing an additional radiator in the automatic transmission cooling system. In addition, in the case of long towing a trailer, the use of overdrive is undesirable. It is better to do it on the ranges of "3" or "2".
20. Do I need to warm up the automatic transmission before driving?
The first time after the start of the movement, it is recommended to avoid dynamic driving until the oil in all units has reached the operating temperature. In the cold season, before the start of the movement does not hurt a little warm up the oil in the automatic transmission. To do this, you need to move the RVD to all positions, lingering in each of them for a few seconds. Then turn on one of the ranges of motion, and hold the car for a few minutes with the brake, the engine should be running at idle.
21. What are the main advantages and disadvantages of automatic transmission?
An automatic transmission increases driving comfort. The absence of the need to choose the right gear and the implementation of gear changes, allows you to focus on driving, which in a difficult road situation will not interfere even with an experienced driver. Due to the availability of the torque converter, the automatic transmission creates more favorable operating conditions for both the engine and the chassis, which increases their service life, and the automatic transmission control system prevents the occurrence of engine and chassis overloads due to driver errors. A car with automatic transmission is equipped with a passive safety system that does not allow the engine to be started in RVD positions other than "P" and "N". It also prevents spontaneous vehicle movement when parked on an uneven ground, since Remove the key from the ignition lock only in the RVD "P" position. The disadvantages of the automatic transmission should include a lower efficiency (due to losses in the torque converter) than that of the manual transmission, which increases fuel consumption. Although this is not always the case. Modern automatic transmissions in some driving modes allow to achieve higher profitability compared to manual transmissions by maintaining optimum engine speeds and “intelligent” control of the torque converter lock. Another drawback is the somewhat worse dynamic indicators of acceleration of a car with automatic transmission than with a manual transmission, all other things being equal. The difference is not so great and for the majority of drivers is insignificant. And, finally, a car with automatic transmission cannot be started except using a starter. It should be noted that the overwhelming number of drivers with operating experience of both types of transmissions, regardless of the level of wealth and driving experience, give unconditional preference to cars with automatic transmission.
22. What is kickdown?
If the throttle control pedal is pressed all the way while driving, the gearbox will shift down one or two gears. This mode is recommended to use for higher acceleration values, which is useful, for example, during overtaking. Reverse upshift in this case can occur only when the engine reaches maximum speed. If you release the throttle pedal, the gearbox will go into normal operation. It should be borne in mind that on slippery roads during a forced downshift, the drive wheels may start to slip, which can lead to a skid.
23. What does the automatic transmission cooling system look like?
As already noted, the main source of heat dissipation in the automatic transmission is the torque converter. Moreover, at high loads, the heat is sufficiently large. The operating temperature of the transmission is comparable to the temperature of the engine, and may exceed it. Therefore, cars with automatic transmission have a special cooling system, the radiator of which is either integrated into the radiator of the engine cooling system, or installed separately and cooled by air flow. On older cars with a small engine capacity can be found boxes with air cooling system. On the case of the torque converter there are additional external blades, with the help of which they organize the air flow for heat removal.
24. How to start a car with automatic transmission?
Before driving, always press the brake pedal, move the RVD to the desired position, without pressing the throttle pedal. After a light push, you can release the brake pedal and start driving, acting on the throttle pedal for this.
25. What are the available methods to check the status of the automatic transmission? What is a "Stall-Test"?
First, check the level and quality of oil in the automatic transmission. Secondly, the switching on time of the transmission when moving the RVD from "N" to "D" or "R" should not significantly exceed 1 - 1.5 seconds. The inclusion of the transfer can be judged by the characteristic push. Pay attention to the quality of switching during running. When shifting gears should not be "shock", vibration and extraneous noise. The moment of gear change should not be accompanied by an increase in engine speed. An experienced driver on the behavior of the car on the road can make a qualified preliminary opinion on the state of the automatic transmission. For reference: Tacho-Transmishn provides free services - running the car by an experienced driver (test drive), reading fault codes and advice. Another simple method to check the status of the automatic transmission is Stall-Test. The essence of this test is to determine the engine speed with the vehicle completely braked and the throttle control pedal fully depressed. The magnitude of these revolutions can be judged on the health of some elements of the automatic transmission. Immediately make a reservation that Stall-Test must be performed by experienced mechanics. Otherwise, you yourself can disable automatic transmission. In addition, to analyze the performance of the automatic transmission, you need to know the nominal value of the engine speed during the Stall-Test, without the knowledge of which this test will not give you anything.
26. Is it possible to do without automatic transmission repair, if the car sometimes does not go?
Owners of cars with "electronic" automatic transmission in the absence of movement hope that all the problems lie in the failed sensors, after the replacement of which everything will be fine. Problems with sensors may be there, but as they say: "Is it too late to drink Borjomi?". The point is that the control algorithms do not provide for blocking movement in case of any failures in the system. Even if a good automatic transmission to tear off all the wires and sensors, the car will not lose the ability to move. There will be no good dynamics and gear changes, but you can go. The lack of movement forward or backward, even periodically, indicates serious problems already in the mechanical part of the automatic transmission, and the only way out is repair. Sometimes you can hear the statement that the cause of all ills may be a clogged oil filter in the automatic transmission. Like, replace the filter, replace the oil twice, and all problems will disappear. It does not happen. The process of destruction of friction elements is irreversible. Burnt friction clutches are treated only by replacing them, the new oil is not able to recover them.
27. What is the difference between "hydraulic" and "electronic" automatic transmission?
Automatic transmissions themselves are the same in the first case and in the second. The main difference concerns the management system. The control system can be divided into three parts: forming the status signals of the automatic transmission and its control bodies; analyzing and executive. In the case of a "hydraulic" automatic transmission, the performance of all these three parts is ensured by hydraulics by forming the corresponding pressures. In the case of electronic automatic transmission, all signals (input and output) are electrically generated, and only at the end of the chain of control signals is hydraulics used. In addition, an electronic control unit (computer) is used to analyze the incoming information and make a decision. This allows you to make the automatic transmission control system more flexible, providing automatic transmission modes inaccessible to the hydraulic control system.
28. What are codes? Why is the “OD OFF”, “Hold”, “S” or “Check AT” light flashing? Why are there no gear changes?
Здесь речь пойдет об автоматических коробках с электронной системой управления. Работой "электронных" АКПП управляет бортовой трансмиссионный компьютер, который может быть выполнен как в виде отдельного устройства, так и быть совмещен с блоком управления двигателем. В трансмиссионный компьютер поступают сигналы различных датчиков (скорости, угла открытия дроссельной заслонки, положения РВД, температуры масла АКПП и т.д.), расположенных как в АКПП, так и вне ее. Он обрабатывает эту информацию и на основе ее анализа вырабатывает команды (выходные сигналы) исполнительным устройствам в АКПП (соленоидам). Таким образом происходит управление работой автоматической коробкой передач. Компьютер выполняет также и другую функцию - контроля и диагностики неисправностей. Для всех входных сигналов есть допустимые границы их изменения. Если какой- либо сигнал выходит за допустимые пределы, то компьютер записывает в память некоторую последовательность цифр - код (Diagnostic Trouble Code - DTC), соответствующий данной неисправности. Кроме того, компьютер контролирует сопротивления выходных цепей (либо токи, протекающие по ним, что одно и тоже). Для них тоже существуют допустимые границы, при выходе за которые в память записывается соответствующий код неисправности. Кроме того, компьютер может сравнивать показания датчиков оборотов входного и выходного вала АКПП, тем самым контролировать передаточное отношение АКПП. Отклонения вычисленного передаточного отношения от заданного является признаком проскальзывания во фрикционных элементах управления АКПП, что также фиксируется соответствующими кодами в памяти трансмиссионного компьютера. К сожалению, функция контроля передаточных отношений реализована далеко не во всех моделях автомобилей. Для чтения кодов в памяти компьютера требуется специальное диагностическое оборудование - сканер. Сканер позволяет не только считывать коды, но и стирать их, а также с его помощью можно определить показания различных датчиков системы управления АКПП. Процедуру считывания и определения неисправностей по кодам часто называют компьютерной диагностикой. Что произойдет после того, как в памяти трансмиссионного компьютера появится код неисправности? Это определяется алгоритмом программы, по которой работает компьютер. Реакция управляющей системы неоднозначна. При появлении одних кодов никаких ощутимых изменений в работе трансмиссии не произойдет, а другие коды могут вызвать отсутствие переключений передач. Все зависит от того, в каком контуре системы управления произошел сбой. Одни коды носят информационный характер (например, код "отсоединялась аккумуляторная батарея"), а другие приводят к изменению алгоритма работы системы управления АКПП (например, код "обрыв в цепи соленоида"). В случае возникновения серьезных проблем система управления переходит в режим защиты АКПП. У этого аварийного режима есть разные названия: Limp In, Limp Home, Safe Mode и т.п. Алгоритмы работы системы управления в аварийном режиме во многом определяется моделью АКПП. В некоторых случаях система управления перестает отслеживать качество переключений, и они происходят с "ударами". В других случаях в коробке включается вторая или третья передача, и все переключения передач запрещены. В некоторых автомобилях аварийный режим сопровождается миганием, либо постоянной индикацией на панели приборов одного из сигналов, связанных с работой АКПП: "Hold", "S", "Check AT", "OD OFF" и т.п. В случае совмещенного моторно-трансмиссионного компьютера этим сигналом может быть "Check Engine", либо символ в виде контура двигателя. Если ни один из этих сигналов на панели не светиться, то это не означает отсутствие в памяти компьютера кодов неисправностей, но если сигнал есть, то есть и коды в памяти компьютера. Аварийный режим не предполагает эксплуатации автомобиля, он служит только для того, чтобы добраться до сервиса и устранить неисправность. Если этого не сделать, то может получиться так, что из-за незначительной, вовремя не устраненной неисправности, выходит из вся АКПП. Надо иметь в виду, что "электронная" коробка, по сути - исполнительное устройство. Проблемы с переключениями передач, плохая динамика, рывки, "удары" могут быть обусловлены как неисправностью самой трансмиссии, так и проблемами с проводкой и датчиками, а также неисправным трансмиссионным компьютером. Проблемы в бортовой электронике приводят к выходу из строя самой коробки, после ремонта которой ситуация наверняка повторится. И так до тех пор, пока не будет устранена причина неисправности электронной части системы управления, которая не всегда находится в самой АКПП. Как правило, автомобили, поступающие в ремонт, имеют не одну, а целый комплекс неисправностей. Разобраться в этом клубке проблем поможет квалифицированная диагностика. Но не следует ожидать от диагностики чудес, хотя иногда удается быстро устранить проблему и коробка на глазах "оживает". Возможности диагностики имеют объективные ограничения. Компьютерная диагностика далеко не равнозначна для разных типов АКПП. Ее возможности можно оценить, взглянув на полный список кодов для данной модели АКПП. У одних моделей список всех возможных кодов (а значит и контролируемых параметров) состоит из четырех пунктов, а других насчитывает полсотни.
29. Что такое адаптивные автоматические коробки передач?
Опять таки, этот термин больше относится к системе управления, а не к самой АКПП. Развитие "электронных" АКПП привело к появлению адаптивных коробок передач. Разрабатываемые алгоритмы управления становятся все более интеллектуальными, что приводит к появления нового качества в тех же самых, с механической точки зрения, трансмиссиях. Бортовой компьютер следит за манерой водителя управлять автомобилем, подстраиваясь соответствующим образом под нее. Кроме того, в алгоритм работы такого компьютера заложен учет износа в АКПП фрикционных элементов управления. Все это приводит не только к повышению комфортности поездки на автомобиле, но и к повышению его ресурса и экономичности.
30. Что такое Autostick (Steptronic, Tiptronic)?
Это система управления работой АКПП, в которой на ряду с автоматическим, предусмотрен и полуавтоматический режим управления, при котором команду на переключение передачи дает водитель, а качество этих переключений обеспечивает система управления. В зависимости от производителя этот режим имеет разные названия (Autostick, Steptronic, Tiptronic), реализуется он только на автомобилях, имеющих электронную систему управления АКПП, и то не на всех. В автомобилях оборудованных такой системой, РВД имеет специальное положение, в котором включается режим Autostick. Относительно этого положения есть два противоположных, не фиксируемых положения РВД. Эти положения имеют обозначения "+"("Up") и "-"("Dn"), соответственно для переключения на более высокую или более низкую передачу. Режим Autostick является скорее полуавтоматическим, чем ручным, т.к. трансмиссионный компьютер, не перестает контролировать действия водителя и не позволит ему, например, тронуться с высшей передачи, или выбрать передачу таким образом, чтобы обороты двигателя превысили допустимые. В остальном же, полная иллюзия механической трансмиссии. По желанию водителя можно перейти и на обычный автоматический режим управления, переведя РВД в положение "D".
So here. АКПП, работают отлично и крайне надежны во все времена года, кроме зимы. Поэтому рассказываю, как не засадить АКПП если температура ниже 15 град.
1) Надо греть машину до РАБОЧЕЙ! температуры. Маслянный радиатор коробки и двигла один и тот же, а коробка от двигла дальше, поэтому АКПП прогревается ПОЗЖЕ.
2) Если уж очень не втерпеж, догреть хотя бы до 40, а потом на ходу, включив 3 передачу и на скорости не более 40 км/ч до рабочей.
3)Перед зимой смените масло и фильтр. Азбучная истина - но результат отнюдь не азбучный - экономия денег на ремонте.Теперь, что будет, если этого НЕ делать.
В управляющей системе АКПП ("мозгах")есть некоторое кол-во клапанов, состоящих из пластмасски и пружинки, которые открываются от давления. При густом масле давление выше и пластмасску, если вы газанули с пробуксовкой, ломает. Следствие - пружинка с осколками пластика пролетает дальше и клинит шестерни. Поскольку приводная шестерня включения/выключения тоже из пластика - она ломается. Результат - коробка не переключает передачи либо выше 2, либо быстро перетыкается со 2 на 4. Если так поездить - засаживаются фрикционы и ремонт по полной программе.
Для тех, кто любит все делать сам - я бы вообще советовал перед зимой уменьшить рабочее давление на полоборота.
Via wiki & Internet