One of the most common used on cars, including the VAZ brand, is mechanical. Although many modern cars already include in the design automatic device gear shifting. But they refuse to use it.
After all, VAZ, like any other brand of car, is very reliable, unpretentious and requires a minimum of maintenance. It is able to withstand significant loads without any harm to itself. The proof of this is the frequent use of this type of gearboxes on cars participating in various competitions.
But no matter how reliable and simple the “mechanics” is, troubles also happen to it. One of these malfunctions is that the first one does not turn on well and reverse gear. And foreign cars are no exception.
But in order to understand why the first gear turns on badly, you need to disassemble the design at the beginning of this type Checkpoint.
Transmission device
So, the gearbox scheme is quite simple.
There is a housing attached to the clutch housing. In this case there are three shafts - driving, driven and intermediate. The peculiarity of the arrangement of the shafts is such that the driving and driven shafts are on the same axis, and the driven shaft enters the driving shaft at one of its ends. Below them is an intermediate shaft.
On each of the shafts there are gears of different diameters and with a different number of teeth, while some of these gears mounted on the driven shaft can move along it.
Principle of operation
The working scheme of the gearbox is as follows. The drive shaft receives rotation from the clutch disc and transfers it to the intermediate one. If the neutral speed is on on the box, there is no engagement of the gears of the intermediate shaft with the driven one, the car is immobilized, since rotation is not transmitted.
When you turn on any gear, the driver engages the gear of the driven element with a certain intermediate gear. And the rotation begins to be transmitted from the driven shaft to the wheels. The car starts moving.
The necessary gears are engaged by a control unit consisting of three sliders and forks. Each of the forks is dressed on a special groove of the element. That is, the driver, using the gearshift lever and through a special backstage, acts on a certain slider, moving it to one side. In this case, the fork on the slider pushes the gear, and it engages. The change in gear shift speed is influenced by the engagement of gears of different sizes and number of teeth.
To prevent the slider with the fork from returning to its original position, the box control unit is equipped with latches. The latter are spring-loaded balls that enter the grooves on the sliders. That is, there are grooves on the slider in certain places.
When moved to the desired position, the ball detent jumps into the groove, excluding the return of the slider. When shifting speed, the driver must apply more pressure to the slider than the detent spring force in order for the ball to pop out.
This is a simplified description of the design and operation of a mechanical transmission.
Typically, classical models work according to this scheme. On some cars, the scheme may be somewhat different, but the essence of the work is the same - a slider with a fork acts on the gear.
In some cars in the gearbox, the slider responsible for turning on the first speed also ensures that the reverse is turned on. They also have such that the first and reverse gears turn on badly. Of course, this breakdown cannot be ignored.
On other gearboxes, the first speed and the rear are separated and different sliders are responsible for switching them on. In such cars, problems with turning on the first speed may not be reflected in turning on the rear.
There are several options why the first gear turns on badly. It also depends on how the cause manifests itself - it is impossible to turn it on, while everything is accompanied by a metallic rattle from the side of the box, or the speed turns on, but immediately turns off on its own.
Poor switching due to slider
First, let's consider why the first gear turns on badly and the reason for this is the problem with the transmission.
Often the problem with turning on the speed lies in the latch and the slider. The appearance of a burr near the groove for the latch on the slider can easily interfere with the entry of the ball retainer into the groove. When moving the slider, the latch rests against this burr and cannot overcome it without significant effort on the part of the driver. In this case, the gears are very close, but they do not engage, and the teeth of one gear beat against another.
In the future, such a beating can lead to flaring of the teeth, and the impossibility of switching on will already be due to the fact that, due to this flaring, the teeth will no longer be able to engage.
Knocking out speed
If it turns on, but immediately turns off, then the latch may be stuck in the depressed position, so it no longer does its job. It is also possible the destruction of the spring, which presses the ball detent. Without the force of the spring, he will not be able to hold the slider in position.
If a significant amount of force is applied during gear shifting, the shift fork may bend.
If this happens, then the gears will no longer fully engage, and the slider itself will not reach the stop, which will prevent the latch from entering the groove.
The reason for poor inclusion may also be the incorrect installation of the backstage of the gear knob. In this case, the link does not bring the gear to full engagement.
Troubleshooting the checkpoint
Troubleshooting is done by removing it from the car, disassembling, troubleshooting parts, if it is found that some of them are very worn out. Particular attention should be paid to the condition of the sliders and clamps. If burrs are noticed on the sliders, they must be removed with a file. You also need to check the condition of the springs and retainer balls. The springs must be intact, and the latch should move without problems in its seat. If necessary, worn or damaged elements must be replaced.
You should also carefully inspect the inclusion forks for bending. Even slight bending can affect the ease of shifting.
After reassembly, shift adjustment must also be performed. To be precise, the position of the backstage is set.
Clutch malfunctions
Often the reason why the first gear turns on poorly is not the box itself, but the clutch.
Modern transmission gears are equipped with synchronizers that equalize the speed of rotation of the gears, providing ease of engagement.
However, the first speed is not equipped with a synchronizer. If the clutch "leads", then when the pedal is depressed, its complete cessation of the transmission of torque from the motor to the gearbox is not performed.
Because of this, there is a difference in the rotation of the shafts and gears of the first gear, in particular.
In this case, it is rather difficult to engage them, and all attempts to do this are accompanied by a strong metallic rattle.
It is possible that the reverse speed will also not turn on, or it will be difficult to turn on. At the same time, if it was possible to still turn on the gear, the car starts to move even with the clutch pedal fully depressed. An additional sign of clutch problems is that the car jerks when changing gears, especially if some of them are not equipped with synchromesh.
How to check the clutch?
Pointing at and not boxes can help the auto engine. If, when the engine is turned off, all speeds turn on easily, no problems arise, and when the engine is running, the first and reverse gears turn on poorly, or it cannot be turned on at all - you should pay attention to the clutch.
The reason that the clutch "leads" is often its incorrect adjustment.
The release bearing is too far from the release diaphragm or cams. When the pedal is depressed, this bearing is not able to completely squeeze the drive disc from the driven one, and the torque continues to be transmitted. Significant wear can also affect the operation of the clutch, due to which it began to “lead”.
Clutch adjustment and repair
The first thing to do in case of clutch problems is to make an adjustment.
On the different cars it is produced in different ways, but all operations come down to one thing - installing release bearing at the required distance from the diaphragm or cams.
If the adjustment did not help, then you will have to dismantle the clutch from the car, carry out troubleshooting and replace worn elements. Sometimes, over time, wear and tear of all the components of the system. In this case, it is made complete replacement clutch - drive and driven discs, release bearing.
Conclusion
The above are the main reasons that it is difficult to shift gears on a car. Although, as stated at the beginning, if mechanical transmission very reliable, then more often the clutch is the fault of poor switching, and not the box itself.
Some drivers who were “lucky” to notice such a lack of a mechanical box even came up with a kind of rule: the first gear is intended only to start moving, and then the second, third, fourth, fifth are applied.
Of course, this rule is fundamentally wrong, since it is necessary to select a gear from the ratio of the current speed and revolutions crankshaft engine. In fact, you can even park normally only in first gear. Parking in second gear is tantamount to the fact that you will "fire" the clutch or maneuver unreasonably fast. Therefore, absolutely any driver needs to acquire an extremely simple skill that allows you to engage first gear on the go.
Gearbox Theory
Modern cars equipped with mechanical box gear shifting, have synchronizers. Synchronizer is component mechanical box, which acts as an equalizer of shaft revolutions, and is also responsible for the shockless engagement of gears.
It is in the process of pushing the gear lever from the second gear position to the first gear position that we stumble upon some kind of obstacle that prevents us from moving the lever to the first gear position. This obstacle is the synchronizer.
If the first gear synchronizer is new, then the process of shifting gears from up to down takes place without any serious delays.
If a car with high mileage, then the synchronizers begin to cease to perform their direct functions. The driver has to remember the old-fashioned methods of controlling a manual gearbox - these are various gas shifts combined with a double clutch release. Regassing with double squeezing acts as an equalizer of the angular velocities of the articulated gears. The higher the difference in angular speeds, and the higher the wear of the synchronizer for a given gear, the more you have to gas. When the angular speeds are equal, the driver will immediately feel it: the gear lever will easily move into the first gear position.
No force is needed.
Methods for engaging first gear while driving
The easiest way to engage first gear while the vehicle is moving is to not push the lever too hard and wait until the first gear synchronizer engages. Unfortunately, this method is not applicable to some trucks, since the first gear synchronizer is not used in the design of their box. Also, this method of engaging the first gear will not succeed if you are driving a car with a “killed” first gear synchronizer. In this case, you either have to wait a long time for the first gear to be engaged, or forcibly “drive in” the first gear. Neither is a good way out of the current situation. The most optimal method for switching on the first gear during the movement is the method of switching on with regassing. Consider the algorithm of the driver's actions.
Double clutch release
- When driving in second gear, depress the clutch.
- Move the gearshift lever to the neutral position. Release the clutch pedal.
- With the right foot, with the clutch fully released, lightly press the gas pedal. We bring the engine speed to a value of about 2500 rpm. An important note: the higher the difference in the angular speeds of the articulated gears, the more it is required to add engine speed.
- We squeeze the clutch.
- Move the gearshift lever to the first gear position. Important note: if the lever does not move to this position, then you probably did not work hard enough on the gas pedal.
- Slowly release the clutch. The first gear should turn on without jerks, bumps and extraneous sounds.
After a few successful inclusions, you will remember these sensations and will include the first one normally.
But keep in mind that this is a temporary solution, and the gearbox with its synchronizers needs to be repaired. Where? This is another question.
Prices for the repair of automatic transmission Lexus and other boxes can be viewed on the site rekpp.ru
It is better to choose good box makers who can give a guarantee for their work, otherwise there is a risk of falling into overhaul. And this, my dear friend, is big money.
More than 50% produced in the world cars are equipped with an automatic transmission, this is a fact, therefore the issue of making the right decision in the event of an automatic transmission malfunction is very relevant today.
This article will help you understand how an automatic transmission works and what to do if a breakdown occurs.
How automatic transmission works in a car - principles of operation
In modern automatic transmissions, all mechanical manipulations for shifting gears are done for you by hydraulics, i.e. - liquid for automatic transmissions. All "mental" work (when and where to switch) is performed by the control and monitoring unit.
To understand how this happens, it is important to know that The automatic transmission consists of three main parts:
- torque converter.
- planetary gearbox.
- Hydraulic control systems.
Torque converter (GDT), in its purpose, is similar to the clutch mechanism on a manual transmission - with the help of it, the torque from the engine is transmitted to the rest of the transmission. However, structurally, these are completely different nodes. Unlike mechanical clutch, GDT transmits (and increases) torque due to fluid.
Planetary gear (PR) receives torque from the gas turbine engine and transmits it to the drive wheels, while reducing or increasing, depending on the driving conditions of the car.
Hydraulic control system (SGU) using solenoids, opens or closes the shift valves. Due to this, the transmission fluid acts on certain brakes and clutches in the PR. There is a blocking or unlocking of certain gears. Thus, there is a switch to the desired gear.
In earlier automatic transmission models, the “decision” on gear shifting was also answered hydraulic system , i.e. The transmission was fully hydraulic. In modern units, the voltage to the solenoids is supplied by the control and monitoring unit, which receives data on the speed of the vehicle, the number of engine revolutions, the temperature of the automatic transmission and other indicators.
Based on these data, a “decision is made” about switching to one or another gear. Such automatic transmissions are called electronic .
Why the automatic transmission does not turn on and what to do - frequent questions from motorists about malfunctions in the automatic transmission and expert advice
During the operation of the car, various problems with the automatic transmission may occur. However, some faults are more common than others. They will be discussed below.
- Why does the automatic transmission not turn on 1st, 3rd, 4th gear or speed - what to do?
So, let's deal, in order, with each transfer.
- If the automatic transmission of your car does not turn on the 1st speed , and the car starts sluggish movement from the second, most likely, the switching solenoid or the wire going to it from the control unit (CU) has failed. This problem is solved by replacing the defective part.
- In another case, the car starts normally, but does not shift into 3rd gear. The reverse gear works fine. The reason is most likely a stuck valve, which is responsible for switching to this gear. To fix it, you need to disassemble valve train and clean the valve.
- With 4th gear the situation is different. If the automatic transmission does not engage the 4th speed at the required speed and engine speed, first of all you need to check whether the overdrive mode. In this case, on dashboard the “O/D OFF” indicator is normally lit. Another reason is a clogged valve, which is responsible for the transition to Overdrive. Cleaning the valve will correct the situation. However, that's not all. Until the fluid in the automatic transmission is heated to the required temperature, there will also be no shift to 4th gear. Therefore, if everything in the automatic transmission is working, but there is no 4th speed, you should check the temperature sensor transmission fluid and a wire going to it.
- Why does the reverse gear not turn on on the automatic transmission or does it turn on with a blow - causes and troubleshooting
In the event that the reverse speed turns on with a noticeable impact, the most likely reason for this behavior of the automatic transmission is friction disc wear . Friction discs are one of essential elements planetary gear. Their wear indicates that the automatic transmission needs a major overhaul.
If the reverse gear does not engage at all, the problem is the brake band or related parts - the brake band piston, piston cuffs or piston rod. In all cases, the problem is solved by replacing the defective part.
- Why does the parking on the automatic transmission not turn on - how to fix the problem?
It also happens that the car cannot be put into parking mode. Because of this, you can not remove the key from the female ignition. And if you manage to take it out, then you will not be able to start the engine after that.
To determine the cause of the malfunction, first of all, check if the brake lights on your car are working. No matter how naive this advice may sound, it is precisely in wiring diagram brake lights, the selector lever lock is turned on (you switch this lever before starting to move), which is activated when the brake pedal is pressed. If this blocker does not work, you will not be able to remove it from the parking lot or transfer the car to this mode.
In this case, you need to check for a malfunction
- Brake pedal.
- Wiring from the pedal to the blocker.
- The blocker itself.
Another reason - rope failure connecting the lever to the selector on the automatic transmission. In the simplest case, it is enough to adjust the cable. Otherwise, it needs to be replaced.
Another source of failure could be strong mechanical impact (for example, impact) on the automatic transmission pan . In this case, the parking mechanism may simply fail. Repair of such a breakdown will consist in replacing the defective part of the parking mechanism, or the entire mechanism.
- The drive on the automatic transmission does not turn on - what is the reason and what to do?
- Drive mode (mark "D" on the selector lever) - the main mode of movement. If for some reason it does not work, or works - but malfunctions, this jeopardizes both the automatic transmission and the car engine. Because the driving modes in low gears ("L", "2") are not intended for everyday use.
- If the car does not drive when the drive is on - it means that the friction discs responsible for movement in this mode have worn out, or the cuffs of the clutch piston have torn. Usually, in the event of such a breakdown, 1st and 2nd gears work fine. The obvious way to fix the problem is to replace the friction discs and torn cuffs.
As you can see, at first glance, the solutions to problems are quite simple ... If you are well versed in technology and have all the necessary tools for repairs.
To automatic transmission gear worked without breakdowns for a long time, it is necessary.
But, in any case, it is better to entrust your faithful assistant to professionals so that, after trying self repair not to look with surprise at the “extra” details and with regret at a non-working car.
When shifting gears poorly, driving a car becomes not only unpleasant, but also unsafe. Consider the main reasons why gears shift poorly or do not shift at all. And since the automatic transmission and manual transmission differ too much, we will consider them separately.
If you have a mechanic
Poor gear changes on a car with a manual transmission for three reasons. The first of these is a clutch malfunction, when it does not fully disengage (leads). The first sign of this malfunction is that the reverse gear engages with a characteristic crack. The rear reacts to this anomaly more noticeably than the other gears, because it is the only one not equipped with a synchronizer.
The second reason is a defect in the gearbox gear selection mechanism. And, finally, the third is excessive wear of the gearbox synchronizers.
There are also several clutch malfunctions in which manual transmission gears do not shift well:
Excessive wear of synchronizers mainly occurs in those gears that are switched on more often: these are usually first, second and third. The rear one does not fall into this list, since it does not have a synchronizer. When your gear shifts poorly, and you assume that the reason for this is the wear of the synchronizers, firstly, you should only have difficulties with this on the go. Secondly, in this case it switches better if you use a double release.
For those who do not know what a double squeeze is. To upshift: depress the clutch, shift into neutral, release and depress the clutch again, shift into gear.
Backlash in the so-called “helicopter” is one of the reasons for the fuzzy gear shifting
To switch to low: double squeeze must be combined with regassing, that is, when the clutch pedal is released and the box is in neutral, you need to press and release the accelerator pedal. So they switch gears on a car whose box does not have synchronizers. If the box will switch easier using double squeeze, then the fault is that the gears are shifting poorly, most likely, worn out synchronizers.
If the gears shift poorly when the car is stationary with the engine turned off, the malfunction can only be in the gearbox gear selection mechanism.
Look for a breakdown in it or check the correctness of its adjustment. Don't even think about the clutch and synchronizers.
For those who have an automatic
If your car has automatic transmission. It will not hurt you to know the modes in which your machine can operate:
The automatic gearbox has a button on the mode switch with the inscription O / D OFF. When it is turned on, a switch-on prohibition occurs, which upshifts the analog of the 5th gear of the manual transmission. That is, if your machine has 4 forward gears, then for more dynamic acceleration it will use only three lower gears.
About a gearbox malfunction, an automatic transmission is much more complicated than those encountered with a manual transmission, and the chances of repairing it in your garage are small. But despite this, you still need to know something about it, at least in order not to harm it by improper operation.
Automatic gearbox is much more demanding on the accuracy of maintaining the oil level in it than mechanics. Both too low and too high oil levels are very harmful to her. Both can lead to serious damage. In both cases, foaming of the oil occurs. With a lack of oil due to the fact that the oil pump begins to capture air along with the oil. With an excess of oil, it foams up the rotating parts, which in this case are immersed in it. Foamed oil compresses better and has low thermal conductivity. Therefore, if you operate the machine with such oil, the pressure in its control systems will be low. Which will lead to slippage of the clutches and their intensive wear. The deteriorating thermal conductivity will not allow all excess heat to be removed. Which, in combination with low pressure, will lead to the fact that the machine will fail and require serious repairs. 
Foamed oil has a larger volume. Therefore, checking the oil will show too high a level. If you find that the oil level has risen for no apparent reason, you need to turn off the engine and let the oil settle. Then check the level again. If it turns out to be low, you need to safely add the required poria and repeat the test.
The oil level in the machine is checked using a dipstick or through a control hole closed with a plug.
How to check the oil level with a dipstick
- Warm up the oil to operating temperature (for this you need to drive about 15 km).
Choose a flat, horizontal area for measurement. Put the car on the handbrake.
- Move the lever for selecting the operating mode of the box through all positions, lingering in each from 3 to 5 seconds, until the machine operates.
- Leave the mode selector in position P, and in this position determine the oil level.
- Without stopping the engine, remove the dipstick, wipe it dry and re-insert it into the tube until it stops, then pull it out and read the readings. The upper limit of oil traces on a dry dipstick should be at the mark with the inscription hot or in the area with intersecting notches.
In case of insufficient level, oil can be added through the tube into which the dipstick is inserted. Do not forget that the automatic transmission is afraid of dirt, so add only clean new oil. Wipe the dipstick with a clean cloth that does not loose threads.
When checking the oil level, pay attention to its appearance. A dark, burning-smelling liquid indicates that not everything is in order in the unit. First, try changing the oil and filter in the automatic transmission. The milky color of ATF indicates that coolant has entered the box. The coolant softens and inflates the material that the clutches are made of. Do not hesitate to replace such an oil, having previously eliminated the cause of the antifreeze getting into the box, otherwise the machine will suffer significant damage. Coolant can get into the box due to leaks in the oil section in the radiator of the cooling system. In this case, the emulsion will be observed both in the box and in the engine cooling system. 
The most common malfunctions of the machine
- The vehicle does not move forward and reverse is normal. Possible reasons: wear of the forward clutch clutches, a defect in the piston of this clutch, breakage of the rings of the same clutch, jamming of the valve body valves.
- There is no reverse speed, there are only 1 and 2 forward. Probable causes: clutch friction wear reversing, malfunction of the piston of this clutch, damage to the spline connection in the drum housing, another defect of this drum.
- No back, forward everything works. Causes: wear of the brake band, malfunction of the piston of this band or breakage of its rod, defects in the braking package.
- There is no movement either forward or backward when you turn on any mode, there is a shifting push, but the car stands still. Causes: torque converter malfunction, lack of oil, clogged filter.
- Only reverse, 1st and 2nd gears are engaged. Causes: valve jamming in the valve body, low level oils, general wear of pistons and friction clutches of gears that do not turn on.
- a rather complex vehicle assembly that requires appropriate attention and high-quality diagnostics. If there are malfunctions in the operation of the gearbox, driving a car becomes not only uncomfortable, but also unsafe.
To date main problem associated with a malfunction of the gearbox is poor gear shifting (gears). It should be noted that more often this applies to used cars, although on new cars in the budget segment, problems of this kind are also no exception.
Read in this article
Gears turn on poorly: the main causes and breakdowns of the gearbox
As a rule, errors during the operation of the unit lead to violations in the operation of the box. In any case, diagnosis is necessary. In this case, problems that arise when switching the gearbox may be associated with such malfunctions:
Gears turn on tight or do not turn on speeds on a manual gearbox: the main causes of malfunction and possible malfunctions.
