The clarity of gear engagement and the operation of the entire shift mechanism often worries owners of cars with manual transmission. A common problem is that after starting the engine, one or more gears are engaged with great effort or not completely, there is no way to change gears, and when switching on, noises are heard. extraneous noise, appear unnecessary vibrations etc.
Such malfunctions appear unexpectedly, and difficulties when shifting gears can increase gradually. Speeds may be difficult to switch on “cold” and/or “hot”. It is noteworthy that often the gears in a manual transmission shift normally when the engine is turned off.
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Gears are difficult to engage with the engine running: possible reasons
At the very beginning, it should be noted that the inability to engage a gear with the engine not running may indicate a serious gearbox malfunction, which consists of failure of the synchronizers. The second reason could be wear or breakage of the gears. It is also possible that the components and mechanisms responsible for transmitting force from the lever in the cabin to the gearbox when selecting a gear may become jammed.
To accurately determine the causes, in the first case it will be necessary to remove the box for disassembly and subsequent troubleshooting; in the second case, it is necessary to identify and replace broken components. In some cases, it is enough to carry out their prevention: removal, lubrication and careful adjustment.
As for problematic switching when the internal combustion engine is running, then the most on the list frequent malfunctions note:
- lack of gear oil in the gearbox;
- problems with the clutch mechanism;
Low gearbox oil level
An insufficient amount of oil in the box makes the process of shifting gears extremely difficult, but the speeds must be engaged. When switching in this way, a metallic crunch is heard, and when driving in a gear, the transmission begins to make a lot of noise and “howl.”
A complete lack of lubrication in the gearbox will not allow you to change gears, since without oil the synchronizers will not be able to work properly, and the gears in the gearbox will not engage.
Any manifestation of these symptoms requires immediate cessation of operation of the vehicle and checking the transmission oil level in the gearbox. It is also necessary to inspect the gearbox for damage to the housing, oil leaks through the seals and gaskets.
It should be noted that for manual transmissions of many cars, the oil in the gearbox is filled from the factory for the entire service life. In practice, replacement is recommended every 60-80 km. mileage
Clutch faults
Simply put, the clutch is a mechanism that serves to transmit the torque of the internal combustion engine to the transmission, and also opens the engine and transmission so that gear can be changed. Failure of individual components of this unit may make it impossible to shift gears while the engine is running.
Brake fluid leaks
Design of many modern cars assumes that working fluid protrudes for clutch brake fluid. If in hydraulic system If there is not enough fluid in the clutch drive, then the clutch will not engage completely.
Transfers to in this case will turn on slowly or not turn on at all. For an initial check, you should look at the fluid level in the reservoir. If the level is low, it is necessary to check for leaks, eliminate defects and bleed the clutch.
If the fluid level is normal and no other reasons have been identified, you will need to remove the gearbox to inspect the clutch elements. Usually when you try to turn on the speed and there are breakdowns this mechanism There are no loud grinding metallic sounds coming from the gearbox itself.
Gears may not engage or may not engage fully if the fault is related to the clutch basket. Also the reason may be release bearing. If the specified bearing does not move freely along the input shaft or is jammed, then replacement of the part is necessary.
It is necessary to separately add that the primary sign of problems with the release valve is the appearance of a rustling or distinct hum when the car is running. The noise appears only when the clutch pedal is pressed to the floor. Such extraneous sounds may be present both on cold car, and when warmed up. After releasing the clutch pedal, the noise should disappear. A jammed release lever will not allow the clutch to engage, which complicates gear shifting and can also lead to rapid wear and destruction of other elements of the clutch mechanism.
Basket malfunctions are often associated with critical wear of the petals. Wear means that the basket stops performing its functions as it heats up. An increase in temperature leads to the fact that the clutch basket cannot completely remove the pressure plate. The result is very difficult gear shifting after the engine has warmed up a little.
After removing the box, it is necessary to inspect the basket for deformation, signs of overheating and other defects. If found, the element must be replaced.
Another reason why the gears do not engage when the car is running or engages with effort may be a worn clutch disc.
After disassembly, it is necessary to inspect the friction linings on the disk. They should not be critically worn, burnt or damaged, and the disc should not be deformed. Additionally, during the clutch inspection process, a check of the diaphragm springs is required. After replacing failed clutch elements, the box must be well centered during subsequent assembly, and the clutch must be pumped.
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As a result of the constant stress to which the manual transmission and clutch are subjected, most drivers are increasingly beginning to notice problems with shifting gears.
However, not everyone has time to respond to them in a timely manner, because often the only sign of a manual transmission malfunction is not full inclusion gears or starting them with a slight stretch. Therefore, in order to avoid serious problems in the future, you should very carefully monitor such manifestations and promptly eliminate the cause that provoked their occurrence. It is better to immediately seek help from a car service, for example, if you are from St. Petersburg, then here http://spb-avtoremont.ru/p264438239-remont-kpp-mkpp.html.
Finding the reason
The easiest way to determine why manual transmission gears do not engage is in two ways:
1. Stop the engine and turn up the speed - If nothing happens, then the problem is most likely due to faulty synchronizers or gears. To determine the culprit of the breakdown, the manual transmission will have to be disassembled.
2. Start the engine and put the car in gear - If it doesn't work, the problem is in the clutch. Most often, this malfunction is caused by problems such as insufficient lubrication, incomplete engagement of the clutch and lack of fluid in the drive hydraulic system. Moreover, the last malfunction is typical only for cars equipped with a hydraulic clutch.
In any case, in order to determine the true cause, you will have to remove the manual transmission and inspect the condition in which the clutch basket is located, if it is satisfactory, check the volume of fluid that is in expansion tank and if there is a shortage, top up.
Insufficient lubrication
Despite the fact that if there is a lack of lubrication in the manual transmission, the gears are still engaged, shifting them can be quite difficult, since the gears cannot fully engage with each other. In addition, insufficient lubrication can even damage synchronizers over time.
Therefore, if you hear an unpleasant metallic grinding noise when changing gears, check the oil level in the manual transmission and inspect it for leaks. If any are present, replace all gaskets and seals. It would not be a bad idea to also change the oil seals located in the shank and on the input shaft.
Main problems and their solutions
If the previous checking methods did not yield anything and the malfunction that caused problems with shifting gears on the manual transmission is not determined, then you need to inspect the condition in which the clutch basket is located. The main impetus for this should be the fact that the gears stop shifting when the engine is running.
Release bearing - In normal condition, its movement along the input shaft should not be hampered in any way. If it starts to jam in some places and it moves along them with difficulty, then this is the reason. However, do not worry, as it can be solved by simply replacing the problematic part.
Disc wear – To determine how badly it has worn, disassemble the basket and visually assess its condition. There should be no carbon deposits on the friction linings, and the rivets under the disc should not be visible. If one of these problems is present, the disk will need to be replaced. Most likely, after this procedure the problem with switching gears will be solved.
Malfunction of the basket itself - During long-term use of the car, the so-called “petals” that make up the basket wear out greatly, as a result of which they become very susceptible to high temperatures and can no longer cope with the removal of the pressure disk. Often, to determine the condition in which the petals are located, a simple visual inspection is sufficient - its petals will be deformed or show signs of overheating. In this case, the basket will have to be replaced.
Hydraulic booster - If there is not enough fluid in the system or there is air in it, the gears on the manual transmission may periodically not turn on. To diagnose, inspect the reservoir and inspect all drive components, including hoses, tubes and release cylinder. All identified areas with leaks will need to be repaired and the system pumped.
Clutch assembly
If in order to detect a problem with gear shifting you had to disassemble the clutch, be extremely careful when reassembling it. Tighten all threaded connections with extreme care. And be sure to center the clutch before installing the manual transmission. For this purpose, you can use either a special tool or the input shaft, which will have to be removed from the old gearbox.
- a rather complex car unit that requires appropriate attention and high-quality diagnostics. If the gearbox malfunctions, driving a car becomes not only uncomfortable, but also unsafe.
Today, the main problem associated with gearbox malfunction is bad shifting speeds (gears). It should be noted that this most often applies to used cars, although new cars in budget segment Problems of this kind are also no exception.
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Gears don't engage well: the main causes and breakdowns of the gearbox
As a rule, malfunctions in the operation of the box are caused by errors during operation of the unit. In any case, diagnosis is necessary. In this case, problems that arise when switching the gearbox may be associated with the following malfunctions:
Gears are difficult to engage or speeds on a manual transmission do not engage: the main causes of the malfunction and possible problems.
The gearbox is a rather complex unit that requires proper attention and diagnostics. Today, the problem of poor gear engagement is relevant for many vehicles, so it is important to understand how the unit is diagnosed and repaired. From this material you will learn why first gear is difficult to engage, what is the reason for this, and how you can engage first gear if necessary.
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For what reasons do interruptions occur?
The gearbox is not only one of the most complex, but also one of the most basic components in any vehicle. The reasons for malfunctions that make it difficult to engage first gear can be associated with both incorrect use of the unit and driving on a bad road surface. In any case, if you don’t know why the speed turns on poorly, then this indicates a certain breakdown of the unit itself.
It should be noted that a similar problem often occurs in older cars that are bought second-hand and not at car dealerships. Therefore, if you purchased a used car, then you shouldn’t even be surprised by such a problem, especially since similar faults will appear in any car sooner or later. In addition, if you try to turn on the speed and this happens, but very poorly and with great difficulty, then over time the unit selector may completely stop responding to any commands from the motorist. Naturally, not every driver will be able to constantly start driving in second gear, so it is important to understand the reasons why first gear is difficult to engage.
Below is a list of breakdowns that can cause the gear lever to shift gears poorly:
- The problem is that the mechanism does not turn on well, the shutdown is incomplete. This problem often occurs in domestically produced cars and in most cases it is associated with the fact that the cable flies off from the mounting point mechanical clutch. In fact, it is not particularly difficult to identify this - if the cable breaks, the pedal will be sunk into the floor and will not move. This, as you understand, is directly related to the operation of the clutch, and not the gearbox.
- There was a breakdown in the operation of the drive rod for controlling the gear shift mechanism. Then not only the first, but also the reverse and other speeds will turn on poorly.
- Breaking jet thrust unit.
- For unknown reasons, the fastening bolts located on the side or selector rod for selecting the gearbox mode have become loose. The problem is solved by tightening the bolts.
- The transmission gear shift drive was incorrectly adjusted.
- The plastic elements in the gearbox control drive have failed or have expired.
- The link was poorly adjusted. As you know, the purpose of the rocker is very important in connecting the gearbox and the gear selector, so incorrect adjustment may well be the cause of the problem. In addition, the plastic bushings on this link could wear out or fail.
- Failure of synchronizers can also be called one of the most common failures in a gearbox. Unit synchronizers are brass bushings necessary for easier switching of unit modes. Since brass itself is a soft material, it can wear out and wear out during the operation of the vehicle. To correctly diagnose the condition of the synchronizers, you should pay attention to the operation of the gearbox - if a grinding or unpleasant sound appears when shifting gears, then the problem is in them. Moreover, this sound will appear constantly when you try to engage first gear. If only sound appears, but the gearbox selector switches to one mode or another without problems, then a malfunction will occur soon.
- Failure of gearbox bearings. Such a malfunction does not occur so often, one might even say that it is rare, but any motorist can still encounter it. If you are the owner of a car with manual transmission, then the bearings could jam in it, as a result of which the shaft stops rotating along the trajectory. In such cases, it is difficult to engage first gear; at other speeds the problem usually does not appear.
- The box shaft has failed. The unit shaft is usually not subject to operational wear or very heavy loads, but the malfunction may be caused by a factory defect. In the event that even minor mistakes were made in production, the shaft may well break. If so, then the problem of engaging the first gear may be just the beginning of a major breakdown that you will face. As practice shows, often in such cases the unit itself breaks down completely.
- The problem of clutch failure is relevant for car owners with automatic transmission. There are cases when, if the clutches are not functioning correctly, a push occurs when the first speed is turned on, but then everything works fine. The problem can only be solved by replacing the clutches.
You, as a motorist, need to understand that failure of the unit shaft or bearings cannot be diagnosed at home. Only experience and equipment will help you understand this reason. Accordingly, if problems arise with turning on the first speed, it is advisable to immediately contact a professional.
How to engage first gear without harming the gearbox?
Often, inexperienced motorists, turning the gearbox selector from second to first speed, may notice how some difficulties arise, in particular, how difficult it is to engage first gear. In such cases, a novice driver often tries to turn on the speed using force, simply by driving the selector into the desired position. This should not be done under any circumstances, since such actions can be fraught.
Actually, having noticed such a drawback in the manual transmission, motorists developed a rule - the first speed should be engaged only in order to move away. In all other cases, second, third and fourth gears are engaged. Experienced motorists especially often use this rule, but we would like to say on our own that this is fundamentally wrong.
Any driving instructor will tell you that the choice of speed should be based on driving speed and engine crankshaft speed. In principle, even parking normally is only possible in first speed. If you try to park in second gear, you will have to maneuver very quickly, and in such cases there will be a strong load on the clutch. Actually, just like the gearbox unit itself. Accordingly, you must learn one simple rule for yourself - you can engage first gear when driving only if the speed is low and the speed is crankshaft not tall.
Theory of gearbox operation
Every motorist who understands the structure of a gearbox knows that everything modern cars with mechanical transmission are equipped with synchronizers. This element is one of the important components of the unit. The purpose of synchronizers is to equalize the speed of all gearbox shafts. In addition, these elements are responsible for painless and shock-free gear shifting for the box.
It should be noted that directly when the driver pushes the gearbox selector when switching from second to first gear, you can feel an obstacle. This obstacle prevents the activation of the first speed and it is this obstacle that is called the synchronizer. If the gearbox is relatively new or a synchronizer has recently been installed on it, then you will not experience problems with the transition from high speed to low speed. The first gear will be engaged without any obstacles.
But if your vehicle has already traveled more than a hundred thousand kilometers, then this will directly affect the functioning of some elements of the unit. In particular, first of all, synchronizers will stop working normally - they simply will not be able to perform the tasks assigned to them initially. Then the motorist is forced to perform various “tricks” that our grandfathers told us about - these are all kinds of gas changes and so on.
When performing such tricks, the throttle change will act as an equalizer for the gears that are connected to each other. Thus, if the difference in angular speeds is high, and the synchronizers are worn out quite badly, then the driver will have to accelerate even more. In the case when the angular speeds are the same, the motorist will immediately understand this - the gearbox selector will be able to switch from high speed to low speed without any problems. Thus, it will no longer be worthwhile to make efforts.
Methods for engaging first gear
So, if the modes in your vehicle are difficult to engage and you have already understood the reasons and theory, then let’s move on to the most important thing - methods for engaging first gear. Most simple method in this case, the first gear will be activated when driving the car. You need to push the unit selector forward without any effort and do this until the corresponding synchronizer comes into operation. However, it should be noted that this method is relevant for most passenger vehicles and some trucks.
It should be taken into account that this cannot be done in most old trucks, since the design of the unit itself does not allow this, since they simply do not have synchronizers. In addition, you need to take into account that this method of activating the first speed is hardly relevant if the synchronizer on your vehicle has already exhausted its service life. This will simply be impossible.
Then the driver will only have to wait a while until the car practically stops in order to turn on the desired speed. Or use force to engage the gearshift lever. In principle, neither the first nor the second method can be called the optimal solution to such a problem. As practice shows, it is best to use the same old-fashioned method with re-gasping.
You can find out how to do this below:
- So, while moving in second gear, start depressing the clutch pedal.
- When you press the pedal, move the gearbox selector to the neutral position. Having done this, you can disable the clutch pedal.
- Then, when the pedal is completely lowered, you need to lightly press the gas with your right foot, pressing the pedal. In this case, pay attention to the tachometer, which shows the number of revolutions. You need to increase the revolutions to two and a half thousand per minute, that is, the needle should be at the number 2,500. Here, pay attention to one important nuance - the greater the difference in angular speeds of the mating gears of the box, the higher the number of revolutions needs to be raised. That is, 2,500 is the minimum, add gas if necessary.
- Then depress the clutch pedal again.
- Next, the box selector should be moved to the initial mode activation position, that is, first speed. Here, also pay attention to the fact that if the selector does not enter the required position correctly, then most likely you simply did not give enough gas. If this is the case, then repeat the steps, only add more gas.
- As a result, you need to release the clutch pedal smoothly, not abruptly. If you did everything correctly, the gearbox lever will move to the required position without any problems, shocks or extraneous sounds.
If you were unable to do this, then do not be discouraged - rarely does anyone succeed in performing a double gas change the first time. By repeating the procedure several times, you will be able to remember everything that needs to be done to correctly engage the first speed. Actually, the same methods allow you to activate first gear when driving in third, for example, if emergency situation you need to slow down the engine. In this case, the higher the driving speed, the longer you will need to wait for the synchronizers to help you. Or you need to press on the gas more.
But do not regard double throttling as a way out of the situation. This method can be called a temporary solution, but the unit will still have to be repaired. Since replacing synchronizers is sufficient complex process, we recommend that you seek help from specialists. If you still decide to perform this procedure yourself, then the instructions provided below will be useful to you.
Some drivers who were “lucky enough” to notice such a drawback of a manual transmission even came up with a kind of rule: the first gear is intended only for starting the movement, and then the second, third, fourth, fifth are used.
Of course, this rule is completely wrong, since it is necessary to select a gear based on the ratio of the current speed of movement and the engine crankshaft speed. In fact, you can even park normally only in first gear. Parking in second gear means you'll be firing the clutch or maneuvering unreasonably fast. Therefore, absolutely any driver needs to acquire an extremely simple skill that allows him to engage first gear on the move.
Theory of gearbox operation
Modern passenger cars equipped with a manual gearbox have synchronizers. The synchronizer is component mechanical box, which acts as a shaft speed equalizer, 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 come across some 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 from upshift to downshift occurs without any serious delays.
If the car has a high mileage, then the synchronizers begin to stop performing their direct functions. The driver has to remember the old-fashioned methods of controlling a manual transmission - these are various throttle shifts combined with double clutch release. Re-throttle with double squeeze 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 will have to throttle. When the angular speeds are equal, the driver will immediately feel it: the gearshift 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 car is moving is to not push the lever too much and wait for the moment when the first gear synchronizer is activated. Unfortunately, this method is not applicable on some trucks, since the design of their gearbox does not use a first gear synchronizer. Also, this method of engaging first gear will not be successful if you are driving a passenger car with a “dead” first gear synchronizer. In this case, you will either have to wait a long time for the first gear to engage, or forcefully “drive” the first gear. Both are not a good way out of the current situation. The most optimal technique for engaging first gear while driving is the technique of switching on the throttle. Let's consider the driver's action algorithm.
Reversing with double clutch release
- When driving in second gear, depress the clutch.
- Move the gearshift lever to the neutral position. Release the clutch pedal.
- With your right foot, with the clutch fully released, lightly press the gas pedal. We bring the engine speed to about 2500 rpm. Important note: the higher the difference in angular speeds of the mating gears, the more engine speed needs to be increased.
- Depress 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 the gas pedal hard enough.
- Smoothly release the clutch. The first gear should engage without jerking, knocking or extraneous sounds.
After several successful starts, you will remember these sensations and turn on 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? That's another question.
Prices for repairing Lexus automatic transmissions and other gearboxes can be found on the website rekpp.ru
It is better to choose good box specialists who can guarantee their work, otherwise there is a risk of getting caught major renovation. And this, my dear friend, is big money.
