Noise in the box. 7 reasons why the gearbox is noisy

When operating a vehicle, it is necessary to monitor the functions of each unit and vehicle systems. Experienced drivers can understand the condition of the transmission of a running car by the nature of the sounds produced by each mechanism. Listening to the car is carried out both while driving and when the car is stopped. A working automatic transmission makes almost no extraneous knocking, noise, squeaks, vibrations, etc. If the automatic transmission is noisy, diagnostics must be carried out to prevent damage to the components and parts of the gearbox.

Why is the automatic transmission “noisy” - When driving or shifting?

Determining the nature of the malfunction by sound

In addition to the skills in qualified repair work, the responsibilities of auto mechanics at service centers also include the ability to diagnose vehicle components. Experienced technicians must accurately determine the area where breakdowns occur in automatic transmissions and the degree of their neglect. From a wide variety of sounds, it is necessary to identify suspicious non-standard noises emanating from a faulty car transmission.

To eliminate noise that is not related to the stable operation of the automatic transmission, the mechanic first checks the following devices:

When identifying the causes of unusual noise in an automatic transmission, both during movement and during a stop with the engine running, an experienced technician pays attention to:

The cause of the noise when the automatic transmission is engaged in reverse gear is also checked. The results obtained during the diagnostic process provide the basis for an accurate assessment of the structure and degree of damage to the automatic transmission.

Separation of the noise of a working automatic transmission by type

Depending on the nature of the sound of the automatic transmission, unusual noises are divided into the following categories:

Features of noise from automatic transmissions, determination of the nature of breakdowns, methods for eliminating them

When stopping a vehicle, you can often hear a sound similar to the piercing wail of a siren. This type of noise occurs when the torque converter is operating. This signal should not cause much concern to the driver if it is short-term in nature. The appearance of an incessant howl, changing the tone depending on the engine speed, indicates the appearance of serious defects in the automatic transmission:

What causes the buzzing noise? It has been noted that the intensity of noise of this type depends on the rotation speed of the output shaft of the power unit. They arise due to increased vibration and oscillations of the line pressure oil valve (regulator valve). To eliminate unpleasant noise, it is necessary to replace thinned oil seals, cuffs and other sealing elements that have failed.

Continuous rattling appears when the engine is running at low speeds. In this case, you need to check:

What do metallic clanging noises indicate when idling? Typical causes here are worn clutch friction disc gaskets. To eliminate this defect and replace the clutch packs, you will have to dismantle the automatic transmission using special lifting equipment in a service station.

The hum and rattle in the area where the differential mechanism is located is the result of problems arising in this device:

What does the noise in the automatic transmission indicate when you engage a gear or change from one mode to the next? The main reason is a malfunction of the operating gear elements in the corresponding rows of the planetary mechanism. When noises change in volume and pitch when the next gear is engaged or the automatic transmission selector is switched to reverse mode, most likely the thrust bearings (liners) have become unusable.

Knock when switching automatic transmission: main faults

So, one of the common reasons why owners of cars with automatic transmissions turn to car repair shops for diagnostics is the appearance of noises and knocks in the automatic transmission. Typically, a knocking sound when shifting gears is accompanied by incorrect operation of the unit, but this does not always happen.

In any case, if the driver clearly hears that the automatic transmission is knocking in the box, then this is a reason to stop using the vehicle and carry out in-depth diagnostics.

If there is a knocking noise in the automatic transmission, the causes of the malfunction may be different. The fact is that an automatic transmission (especially when it comes to hydromechanical automatic transmissions) is a complex unit that includes a large number of mechanical, hydraulic and electronic components.

To identify the source of automatic transmission knocking, just look at the list of common faults:

low or high level of transmission oil in the automatic transmission;
incorrect clearances between brakes and clutch packs;
stuck valves in the automatic transmission valve body or mechatronics;
problems with solenoids, pressure regulator;
malfunctions in the operation of actuators, automatic transmission ECU;
wear or damage to individual elements in the box;
wear of engine and automatic transmission mounts, etc.

It would seem that there are a lot of reasons and knocking in the automatic transmission, as well as impacts in the automatic transmission, are extremely difficult to localize (especially in the case of a hydromechanical automatic transmission when changing gears). However, in practice, in some cases it is possible to determine a breakdown by the nature of the knock.

First of all, when changing gears in an automatic transmission, the angular acceleration of the output shaft through which torque is transmitted is constant. In this case, the angular speed of the pump wheel and turbine wheel in the torque converter changes. Also, the crankshaft of the internal combustion engine rotates at different frequencies.

Due to the presence of a large number of ECM sensors, various processes are “monitored” by electronics, and errors are recorded in case of certain failures. As for the automatic transmission, if there is an automatic transmission error, this makes the task easier. However, often knocks and knocks are not displayed as a fault code, which can be easily read during diagnosis from the automatic transmission ECU using diagnostic equipment.

In simple words, the automatic transmission may knock during operation, but there are no diagnostic errors. This means that there is a problem, but the system cannot recognize and record problems in the automatic transmission

In such a situation, it is important to understand that manufacturers of many gearboxes have, until today, not been able to implement effective control over all processes in the transmission (due to the complexity of the unit devices).

For example, a malfunction of the automatic transmission differential leads to a grinding or knocking sound in the automatic transmission in the place where the differential is installed. The reason is wear of the differential drive or driven gear, wear of the differential bearing, and an increase in the axial clearance. It is also possible that the pin of the pinion gears in the differential may become stuck, causing noticeable play.

In some cases, knocking in the automatic transmission appears as a result of problems not with the box itself, but with the gas turbine engine. In this case, the torque converter often knocks due to its own malfunctions or imbalance.

If the driver notices knocking noises in the automatic transmission when shifting, this knock may well be the reason that there are problems in the gas turbine engine. It must be remembered that the higher the angular speed of the turbine wheel of a gas turbine engine, the more energy is released.

In a situation where the change in angular velocity differs from the calculated one, this leads to switching, which is simultaneously accompanied by knocking. Another knocking sound in the automatic transmission when reverse gear is engaged and increased vibration are the result of the inertia of the turbine wheel due to a sharp change in angular velocity.

A slight jolt and a slight knock in this case is quite acceptable, but there should be no impact. Also, when detecting knocking noises while engaging reverse gear, it is recommended to linger for 1-2 seconds in “N”, and then move the selector to “R”. Such a change in the habit of switching to reverse gear not abruptly in the case of an automatic transmission will make the switching itself soft and smooth.

If we take into account all of the above, it becomes clear that knocking noise due to problems with the torque converter occurs as a result of failures when changing the angular speed of the gas turbine turbine. As a rule, a change in this speed occurs precisely at the moment of gear shifting. Ultimately, this becomes the cause of the knocks that the driver hears.

Automatic transmission hums at speed: main reasons

Let's start with the fact that one of the most common transmission-related problems is transmission noise or transmission hum. This problem is well known to many owners of cars with manual transmission, and quite often a vehicle with a humming gearbox is quite suitable for further use.

In other words, if a manual transmission is humming, but the unit itself is working normally, the gearbox is often used for quite a long time without repair. As for automatic transmissions of various types and types, in this case the appearance of automatic transmission hum and noise is a more serious problem.

Next, we will look at why the automatic transmission is noisy or humming, for what reasons the automatic transmission hum appears at speed, during gear shifts, etc., as well as what the owner should do in such a situation.

What's the result?

As you can see, automatic transmission noise is often a sign of a malfunction, rather than natural wear and tear of the unit. In this case, the hum in the automatic transmission is the basis for stopping the operation of the vehicle and conducting in-depth diagnostics.

You need to understand that normally the automatic transmission should not hum or make noise; only a monophonic sound is allowed, which is uniform. If, against the background of the normal sound of the operating unit, extraneous noises begin to be heard, this indicates problems with lubrication or malfunctions of automatic transmission parts.

Finally, we note that the habit of listening to the sounds and noises of the transmission, engine and other units allows you to identify problems at the initial stage when certain signs first appear. In the case of automatic transmissions, this allows you to avoid serious problems and significantly save the money needed to repair the automatic transmission.

Automatic transmission noise or automatic transmission hum: reasons

So, while operating a car with an automatic transmission, the owner must necessarily record all failures and irregularities that may occur during operation of this type of transmission. A working automatic transmission should not normally produce any extraneous noise, knocking, hum, vibration, grinding, etc.

If the automatic transmission is noisy, you should start to find out the cause as soon as possible. The fact is that an automatic transmission is less reliable and structurally much more complex than conventional manual transmissions. Also, automatic transmissions are less adapted to loads, more sensitive to the quality of lubrication, etc.

How to identify automatic transmission faults by sound

The ability to diagnose a unit by sounds applies not only to the engine, but also to the gearbox, as well as other components of the vehicle. The automatic machine is also no exception. This approach allows you to quickly identify suspicious automatic transmission noises in the event of malfunctions and, in some cases, localize the breakdown.

At the initial stage, you need to make sure that it is the automatic transmission that is humming. To do this, you should check the pump, the quality of the engine cooling system, evaluate the operation of the engine, generator, check the timing belts or chain, power steering, steering elements, bearings, etc.

If the noise definitely comes from the automatic transmission, you need to pay attention to its frequency, tone and volume. You should evaluate the operation of the transmission in motion under load in different modes, also turn it on and drive in reverse gear, listen to how the automatic transmission works at idle.

During operation of the automatic transmission, a howling, buzzing, crackling, grinding, hum, etc. may be heard. Metallic impacts of greater or lesser intensity and sounds of surface friction may also be heard. Based on the nature and characteristics of automatic transmission noise, you can determine the nature of the malfunction.

For example, when braking, you can hear a loud sound similar to a howl. This noise is associated with the torque converter and is often not a serious problem if it occurs only briefly. If the automatic transmission howls constantly, and the tone changes depending on the engine speed, then this may indicate the following automatic transmission problems:

Also, in some cases, the automatic transmission buzzes. Moreover, the intensity of such sound directly depends on the speed of rotation of the output shaft. Such noises arise as a result of increased vibration, as well as oscillations of the line pressure valve (regulator valve). To get rid of the problem, it is often enough to replace the seals, cuffs and other sealing elements.

We also recommend reading the article about why the automatic transmission kicks and pushes. From this article you will learn about the main reasons why kicks and jolts of an automatic transmission occur; an automatic transmission jerks on the move, when switching speeds, modes, etc.

Often rattling can be heard in the automatic transmission, especially when the engine is running at low speeds. In this case, diagnostics of the gas turbine engine is needed to determine its performance. Possible problems include damage to the hydraulic pump blades, problems with the turbine wheel, and malfunctions of the damper springs.

Frequent vibrations and rattling while driving appear as a result of damage to the engine flywheel, to which the torque converter is attached. In this case, a characteristic feature is that the vibrations disappear for a short time if the selector is switched from mode “D” to “P” or “N”.

Even when idling, you can hear the clanging of metal in the automatic transmission area. Often the cause is clutch gaskets (friction discs) that are sufficiently worn out. To eliminate such automatic transmission clanging, you need to change the clutches in batches. This operation involves removing the automatic transmission.

You can also often hear a hum and grinding noise in the differential area. This noise is often mistaken for wheel bearing noise. If the automatic transmission differential hums, this may indicate that the gear teeth, bearings and other elements of the mechanism are worn out.

In this case, the problem must be solved immediately, since the differential elements are likely to jam, play in the satellite occurs, wear increases, etc. At the same time, noise may occur in the automatic transmission when the gear is engaged, when the driver switches from one operating mode of the automatic transmission to another. Most often, the cause is wear or breakdown of the elements of the gears involved in the ranks of the planetary mechanism.

If the noise changes (becomes louder, the pitch changes) when the automatic transmission selector is switched to R (reverse) mode, this often indicates that there are problems with the thrust bearings (liners).

Source

Noise from the transmission during heavy acceleration

Car Astra H engine 1.6 XE1 manual transmission F17.
To 70 thousand. mileage there was a hum from the gearbox. It manifests itself during intense acceleration in first or second gear, and persists in third, but much weaker, merging with other noises. The sound is similar to that of a gear, like when driving in reverse. The intensity of the hum is directly dependent on the torque, so the faster you accelerate, the stronger the hum. As the torque decreases, the noise practically disappears. The difficulty is that periodically the noise disappears. Another point: on long trips (maybe when the gearbox warms up well), the noise also goes away. When passing the next maintenance, I asked the official dealer to look at the box, voicing the symptoms. They fixed the right wheel bearing, changed the hub, eliminated some of the noise, but the gear noise from the box remained. The dealer himself said that everything was fine with the gearbox, nothing was found at the stand, the oil level was normal.

I searched the forum. There are 2 options: - either a differential - or the main pair of manual transmissions (which is very sad)

One thing confuses me: why does the sound disappear periodically if this is (let's say) the main pair of the box?

Can anyone tell me, from their own experience, what the possible faults might be?

It just means that on the weekend I wanted to drive up to knowledgeable people at a car service center, how.

The day before yesterday I was driving around the city, accelerating in second, just about to switch to higher. Then, not far ahead, a car suddenly brakes. I let off the gas pedal, slow down with the engine, without turning off or changing gears, I manage to change lanes. I accelerate again, drive further and feel something is wrong. After a few seconds, I realize that my musical ear no longer registers the painfully familiar noise from the box during acceleration. He's gone! I deliberately drove the car in different modes, accelerated faster - silence. There is noise from the tires, there is a rumbling sound from the engine, but there is silence from the gearbox. I want to find fault, but there’s nothing to it.

Okay, I think the box is warm now, we'll see the next day when it's cold.

The next day I leave, accelerate, preparing to hear familiar sounds. But no. Silence.

How so. This noise bothered me for several months, but now...

I'm at a loss myself. What was it?

I think no one will argue that any gearbox is one of the most key parts in a car. Therefore, all problems that sooner or later arise with the checkpoint must be eliminated in a timely manner. After all, this is a rather serious mechanism, the repair of which in certain situations can be very expensive and comparable even to engine repair.

During operation, the box may exhibit various troubles that stand out not only due to the characteristic sound. But, using today’s example, let’s take the hum as a basis, what problems can it indicate and what consequences can the car owner expect?

What’s interesting is that howling can be completely different, differ from the intensity of traffic, speed, gear engaged, etc., but its symptoms usually boil down to one list of problems.

By the way, it may not always indicate that problems have arisen with the checkpoint. It is quite possible that this is a design feature of a particular mechanism or the device has just been repaired, that is, the parts have not yet gotten used to it. In addition, the cause of noise can be not only the gearbox itself, but also the units associated with it, for example, the clutch, if we are talking about “mechanics”. The spring has become loose, the release bearing has worn out, etc.

Rumble on the "mechanics"

The manual transmission is widely used, having a not very complex system structurally, but there are plenty of reasons why noise can be heard.

For example, when the gearbox is in neutral and the clutch is depressed, a howl is heard; in most cases, the cause of this is a worn input shaft bearing or drive gear bearing. The same thing happens when you release the clutch and there is a noise, it's all about the input shaft bearing.

In general, there can be many reasons causing extraneous sounds, even in “mechanics”:

• Wear of the main elements of the main pair (shaft, gear).

• Wear of shaft bearings and gears. In this mode, they can work even for several months, but after such neglect will result in expensive repairs.

• Problems with individual gears (teeth worn out or crumbled), for example, if a howl is heard only when a certain gear is engaged.

Noise in automatic transmission when cold: reasons

If the problem only appears when it’s cold, you can still drive, but when the gearbox does not stop making noise even when the unit is warmed up, then specialist intervention is necessary. Delay may result in serious damage.

The cause of the noise when the box is not yet warmed up is especially often the jamming of the generator pulley clutch. You can try opening the hood and driving back or forward a little. It will be clearly visible how the transmission belt jerks.

Typically, drivers immediately change the belt and tension pulley. Yes, the problem may be in them, but you still need to inspect the pulley first. To check it, you need to rotate the pulley several times, first in one direction and then in the other direction. If the pulley does not move smoothly when turning, it will have to be replaced. Work here for 10 minutes.

Why does first gear howl in an automatic transmission?

Sometimes the gearbox hum only appears when driving in first gear. When switching to the second, the unpleasant sound disappears. This means that the problem is in the planetary gear, or rather, in one of its satellites - a group of gears. Over time, the howl of the automatic transmission in first gear only becomes stronger. This leads to transmission scattering and complete engine stop.

The planetary gear needs to be repaired. You can, of course, not rush into a trip to the service station and wait for the mechanism to completely collapse, but such a delay can hurt your wallet. A complete replacement of a planetary gear is more expensive than repairing one of its planetary gears.

By the way, if an unpleasant sound appears only during forced (fixed) transmission, then there is no need to rush into repairs. Try changing the working fluid. But if the noise also appears while driving, this is a serious matter.

Robot gearbox malfunction

The “robot” gearbox or DSG (Direct Shift Gearbox) is distinguished by the fact that it has a clutch that is switched by computer command using an electric or hydraulic actuator. There are single-disc and double-disc robotic boxes. Therefore, some of the signs and reasons are related specifically to the peculiarities of its work.

Signs of robotic box malfunctions

External signs of a broken robotic gearbox are similar to the other types of transmission described above:

The warning lamp on the instrument panel lights up.
While the car is moving, a buzzing or crunching noise emitted by the DSG is detected.
When the engine speed increases while driving, the speed does not increase. In general, the dynamic characteristics of the car decrease.
Transmission oil leak.
The clutch slips.
When shifting gears up or down, a jolt or jerk is felt.
Complete failure of the robot box.

When the Check Engine warning light on the dashboard is activated, you must scan for errors using a special scanner. This will help localize the cause of the breakdown.

Causes of DSG malfunction

Mechanical problems with a robotic gearbox are in many ways similar to similar problems with a manual transmission. Is it possible to single out two special ones:

Due to a worn gear selection fork, the selected gear may not be engaged.
Rolling bearings in control mechanisms wear out over time and produce a hum or crunch.

If the robotic gearbox is equipped with an electric clutch drive, then it is characterized by the following breakdowns:

Burnout of contact groups. This is due to the fact that over time their cooling system is disrupted. And this, in turn, occurs due to the fact that the oil channels through which the coolant passes become clogged. To avoid such damage, you need to periodically clean the contacts and change the oil in the box on time.
Breakdown of switching drives. In particular, over time, the teeth on the gears grind down, and the levers dangle freely. This will cause the clutch to work abnormally and the car will jerk when driving. For repairs, you need to inspect and replace worn parts.
Burnout of drive motor brushes. Because of this, the shift levers may not work. The brushes on the engine must be periodically inspected and replaced with new ones.
Control unit malfunction. This is a fairly rare failure, and it usually consists of the software installed in it crashing or starting to work incorrectly. And this, in turn, can result in incorrect behavior of the entire gearbox. In this case, flashing the control unit helps. It is not recommended to do this on your own; it is better to seek help from a car service center.
Dirty radiator cooling fluid DSG. Due to overheating, the control unit of the robotic gearbox may also malfunction.

Automatic transmission hums at speed: what to do?

There may be a buzzing noise in the area of the gearbox when accelerating. As a rule, the automatic transmission hums at a certain speed limit, and then the hum only intensifies. A detailed diagnosis reveals that the place where the noise is generated is the rear part of the automatic transmission, where the connection to the driveshaft occurs. In this case, the system does not generate any errors. This is not yet a reason to panic, and the appearance of unpleasant sounds in this area is not evidence of the “death” of the gearbox. A possible cause is a broken transfer case front bearing (the bearing closest to the front driveshaft).

With such a malfunction, almost all bearings in the transfer case need to be replaced. For repairs, the box will have to be dismantled. The problem is that the transfer case is located in the same unit with the automatic transmission.

Repair procedure:

What to do if a hum begins to come from the box?

The best solution in this situation is to immediately go to a good service station to obtain information about the nature of this hum. If a specialist, after diagnostics, says that wear has begun on the main pair or other gears of the box mechanism, you can safely drive for a few more weeks, collecting money for repair work. But remember that wear on the main pair shaft sometimes has a negative impact on the condition of all gearbox mechanisms. So you may well get the situation to the point where your box will have to be sent for major repairs or even replacement. The box repair algorithm is as follows:

bring the car for a quality service with a sufficiently large number of specialists and good equipment for repairs;
To begin, order disassembly and complete detailed diagnostics of the gearbox to identify problems;
If you identify a problem, estimate the cost of restoring the car and potentially repairing your box;
make a decision based on the proposed facts and provided information from specialists;
Order gearbox repairs from professionals whom you completely trust - poor quality repairs cannot be tolerated;
install only original expensive parts inside the box, as they can last a long time and have a guarantee.

One of the most expensive processes in transmission repair is disassembly and diagnostics. Then everything is done at affordable service station prices. You need to keep this in mind when choosing parts for your transmission. It is best to use original factory spare parts to completely eliminate troubles in the near future. This way you will save on subsequent repairs and can easily complete the necessary tasks in one process of disassembling the box. You should not skimp on parts and the quality of work performed, as this may negatively affect the operation of the unit. We suggest considering the reasons for the hum in the box, which experts talk about:

Automatic transmission hums when accelerating

Sometimes the car makes unpleasant sounds when starting to move. Perhaps it's the automatic transmission whining. It starts making noise when shifting into third gear or at a speed of 60 km/h. With further acceleration, the unpleasant noise intensifies. After reaching a certain speed (80-90 km/h), the sound from under the hood subsides. If you stop pressing on the gas, the sound will no longer appear, but further acceleration will provoke its appearance again.

Replacing the rear gearbox can solve this problem. It is also worth inspecting the rear brake discs. You need to check the back side (where the brake cylinder is located). Rusty deposits may accumulate on the discs. If their width is more than 1 centimeter and they are over the entire surface, this may cause extraneous noise. The problem is solved by cleaning the inside of the disks.

Automatic transmission whine when shifting gears

Sometimes when you start driving, you can hear a suspicious sound resembling a howl from under the hood. This usually happens when shifting into second gear. In most cases, the source is the front planetary gear. This unit begins to make sounds when the transmission is heavily worn. Some drivers do not attach much importance to this and wait until the planetary gearset completely falls apart and a “meat grinder” of gears is formed, but this should not be allowed to happen.

The constant desire to reduce the cost of mechanisms simply cannot but affect their quality. The planetary mechanism quickly begins to break down the axes of the satellite gears. This leads to a change in the contact patch between the sun gears and satellites, which causes the destruction of their “teeth”. There is only one way out of this situation - replacing the planetary mechanism.

What noise additives are best to use?

There are many additives to eliminate noise. Manufacturers promise that their use will increase the service life of the mechanism and ensure smoother operation of the automatic transmission. Let's highlight the following additives:

The appearance of extraneous noise in the automatic transmission area is a reason to diagnose and repair the mechanism. A normally operating automatic transmission never hums or makes a grinding noise; it emits only a uniform, monotonous sound. The presence of noise is a sign of a malfunction that can occur both in the selector and in the working part of the mechanism.

Source

Gearbox noise

The causes of noise in the gearbox depend on the type of transmission. So, in manual transmissions, a hum may appear, for example, due to wear of bearings, shaft gears, springs on the rocker, or differential. As for the automatic transmission, most often it hums due to low oil level, due to problems with the torque converter and the lever linkage.

To eliminate noise in the area of the box, it first makes sense to check the oil level in it. If it is not enough, then you need to top it up or replace it. As a temporary solution, an anti-noise additive is sometimes used in the box (it will not completely remove it, but at least reduce the operating noise). To effectively eliminate hum, the box should be dismantled, checked and fully repaired. Read about all the causes of noise in the gearbox in the article, and for brief information on why various types of noise appear in the gearbox, see the table.

Diagnostics of the gearbox at the station - main points

There are many solutions you can take to improve the performance of the transmission in your car. If you heard a hum at a checkpoint, you should immediately go to the station. If the technician tells you that the problem is not too urgent, you can postpone the repair, collect the required amount of money and obtain the necessary equipment reliability. But if the matter is urgent, you will have to resolve issues as quickly and efficiently as possible. Therefore, a good diagnosis from a professional service will definitely not be superfluous. All you have to do is bring the machine to the service and describe the manifestations of the problem that are occurring. Diagnosis is possible in various manifestations:

the technician may ask you to take a ride in your car to hear the humming live and make a verdict on the possible problem based on the sound of the car;
it is possible to connect various diagnostic equipment and attempt to launch independent vehicle diagnostic capabilities to obtain the necessary data;
there is also the possibility of lifting the car on a lift and turning the box using axle shafts to understand all the features of the current situation;
the service may offer quick dismantling of the gearbox, which will cause certain costs for the car owner, but will give the most reliable result;
after dismantling, the breakdown of the gearbox will become obvious, it will need to be repaired immediately, since you will have to pay again for the removal and installation of the box otherwise;
specialists from many services can independently find the necessary spare parts and carry out repairs within a few hours if you need the car urgently.

With the help of many modern solutions you can achieve excellent quality restoration. Most likely, during the diagnostic process, specialists will determine not only the problem that caused the hum in your car’s gearbox, but will also find several other breakdowns. They should also be eliminated so as not to have to disassemble this complex assembly again after a short period of time. No matter what you repair in your car, all related problems should be corrected immediately after identification. Eliminating them in the early stages allows us to obtain the maximum necessary operating features, reliability and quality of the car to the fullest.

Why is the gearbox noisy?

Most often, noise in the gearbox, both manual and automatic, occurs when the oil level has become lower or the gear lubricant is no longer suitable for use. The nature of the sound resembles a metallic clang, which intensifies as the vehicle speed increases. So, noise in a gearbox with a low oil level occurs:

ATF level dipstick

The reason for the hum from the gearbox when the engine is running cold may lie in the thickness of the transmission oil and its contamination.

The next common reason why a gearbox hums is partial failure of the bearings of the primary or secondary shafts. In this case, the sound will resemble a metallic hum. The input (drive) shaft bearings will hum in the following situations:

If the bearings of the secondary (driven) shaft fail, the hum of the box will be observed:

Bearing of the input shaft of the VAZ-2110 gearbox

If there is significant wear on the gears or synchronizers, a situation may also arise when the gearbox howls. The sound is reminiscent of a metallic clang, which intensifies as the engine gains speed. As a rule, the hum occurs in one specific gear. This raises additional problems:

As for automatic transmissions, a hum can also occur due to bearing wear, low oil level, and gear wear. However, with an automatic transmission, a hum can also occur if it fails:

Eliminating noise

Let's look at the signs and corresponding breakdowns of the gearbox in the VAZ 2109

Signs

Replacing the drive shaft bearing

If you decide to repair the drive shaft bearing yourself, then for this you will need a hammer, a vice, and a bearing puller. Let's start the repair:

First you need to dismantle and disassemble your gearbox; then take the drive shaft and clamp it in a vice

Attention! The vice must have soft metal pads; the rear bearing must be pressed using a special puller; then turn the shaft over and compress the inner race of the primary bearing in the same way; Now you need to push the rear bearing all the way onto the shaft. This is done using a metal mandrel and a hammer; the same operation must be done with the inner ring of the front bearing.

Add oil

If you decide to fix the noise problem by adding transmission fluid to the box, then prepare new manual transmission oil and some rags in advance:

we find the dipstick for monitoring the fluid level in the box - it is located in the engine compartment on the left side, next to the battery;
take out the dipstick and wipe it with a rag;
then insert the dipstick back all the way and pull it out. The transmission fluid level should be somewhere between o and “Max”;
if you see that there is less oil than necessary, then take a new one and fill it through the hole to check the level to o.

Replacing locking rings

To replace the rings of the locking mechanism, perform the following steps:

remove and disassemble the gearbox;
we find the blocking device;
We see blocking synchronizers on it: you need to visually assess their condition. If fragments are visible on the rings or they themselves have expired their service life, then they need to be replaced;
We put the box back together and put it in place.

If the hum in the manual transmission appears as a result of wear on the rings, then when they are replaced, the extraneous sounds will disappear.

Replacing the synchronizer clutch

Here you need to stock up on clutch and patience in advance:

Having disassembled the gearbox, you need to remove the secondary shaft synchronizer;
To get to the clutch, the synchronizer must be completely disassembled. Be careful - the parts are very small and can be easily lost. The clutch is a small ring on the inner diameter of the synchronizer;
Having disassembled the synchronizer, check all its components for mechanical damage. If the springs are too stretched, then it is also better to replace them with new ones, but you need to buy a complete repair kit in advance;
before installing the clutch in place, lubricate it, as well as all other synchronizer components, with engine oil;

Clutch adjustment

Incomplete disengagement of the clutch is “treated” by adjusting it:

The clutch pedal must be pressed to the floor all the way and a meter or ruler should be placed next to it, one end of which should also be rested on the floor. Then you need to fix the value at the center of the pedal;
now release the pedal and in the uppermost position mark the number of centimeters to it from the floor;
then slowly press the pedal with your hand and mark the place where the clutch begins to provide resistance for further pressing;
the amount of free play is the same distance from the pedal position until the moment the clutch begins to exert resistance;
Now open the hood and look for the cable that connects to the pedal. There are two nuts on it, with the help of which adjustment is carried out;

Adjusting the clutch pedal cable

The transmission is noisy when driving in neutral	the drive shaft bearing has failed; The gearbox runs out of oil.
There is noise coming from the gearbox and periodically disappears when the gears are turned on.	the locking mechanism has failed; synchronizer clutches are worn out; incomplete disengagement of the clutch.

To increase free play, you need to unscrew the nut located inside the bracket. You also need to tighten the nut located outside;
This is where the adjustment lies. If everything is correct, then the full stroke will be about 13 centimeters. If this indicator is significantly more or less, then the adjustment process should be repeated.

Noise additives in the box

Transmission noise reduction additives can temporarily reduce the noise during operation. However, the cause of the hum will not be eliminated. Therefore, it makes sense to use additives only for preventive purposes or during pre-sale preparation of a car in order to get rid of it as quickly as possible.

Different types of additives are suitable for different problems, so when choosing one it is important to determine exactly what is humming in the box. The most popular attachments for reducing noise in manual transmissions are:

There are similar additives in automatic transmissions. Examples for automatic transmissions include:

The additive market is constantly being replenished with new compounds to replace old ones. Therefore, the lists in this case are far from complete.

Conclusion

Most often, a manual transmission is noisy because the oil level in it is low, or the oil is of the wrong viscosity or is old. In second place is bearing wear. Less commonly, wear of gears and couplings. As for automatic transmissions, similarly, most often the cause of the hum is low oil level, wear of gears and bearings, and malfunctions of hydraulic system elements. Therefore, the first thing to do when a howling or noise of a different nature appears is to check the oil level, and then look at the situation, under what conditions it occurs, how big the noise is, and so on.

In any case, it is not recommended to operate any transmission that makes a hum or shows other signs of malfunction. In this case, the box will wear out even more and its repair will cost more. The exact cause can only be found out by disassembling and troubleshooting the unit.

Source

Noise additive in gearbox

As you can see, you can give an affirmative answer to the question whether the automatic transmission can hum. At the same time, as in any other unit, noise in an automatic transmission can appear for various reasons (wear, malfunctions, loss of properties of ATF transmission oil, etc.). It is also a common situation when noise appears in the automatic transmission after changing the oil. This is often due to the fact that unsuitable oils are used, errors were made during replacement, etc.

Owners often note that noise in the automatic transmission occurs in neutral and in parking; in some cases, noise in the automatic transmission appears when the car is stationary or in motion when the gear is engaged. It also happens that the problem manifests itself only under certain conditions and modes (for example, noise in the automatic transmission when engaging reverse gear or howling of the automatic transmission during acceleration).

Moreover, the list of “childhood” diseases allows you to quickly find out why the gearbox on a Lada Granta or other car with a manual transmission is humming. At the same time, diagnosing a manual transmission actually does not take much time. The repair itself is also often limited to changing the oil and replacing the manual transmission clutch or, in the worst case, rebuilding the transmission and replacing worn parts.

When it comes to automatic transmissions, both on domestic and foreign cars, everything is much more complicated. Owners often ask why the gearbox hums on a Lada Granta automatic transmission, or the automatic transmission howls on a Nissan, Lexus, Audi or BMW. So, in this case, diagnosing the cause is difficult and expensive. It is for this reason that quite often owners of cars with automatic or manual transmission begin to look towards additives.

As is known, an additive in a manual transmission to reduce noise or an additive in the transmission oil of an automatic transmission in some cases can reduce or completely eliminate the appearance of extraneous sounds. In practice, manufacturers of such compounds promise normalization of unit operation, increased service life, softer and smoother operation of the automatic transmission, etc.

There are a large number of products from different manufacturers on the market, and among additives for automatic transmissions we can single out Liqui Moly and Xado. In the first case, the Liqui Moly ATF Additive is quite popular.

This additive in automatic transmissions has a positive effect on the oil, slows down its aging and oxidation, and also helps restore the elasticity of rubber and plastic seals. This property makes it possible to stop oil leaks through oil seals, gaskets and seals.

This additive can be mixed with any ATF fluids, since the composition does not contain additives that can lead to the loss of properties of the base oil or lead to swelling of the rubber. In fact, the additive has the same components as oil, only in high concentration. The composition does not affect the coefficient of friction, that is, there is no risk of friction clutches slipping, etc.

You can also select XADO revitalizant (gel-revitalizant EX120) for automatic transmissions. This solution protects the box from wear and tear and is also a means of partial (restorative) repair. According to the manufacturer, the Hado automatic transmission additive protects surfaces and restores rubbing parts, which allows you to get rid of noise.

A special metal-ceramic coating is formed on the surfaces, and the geometry of the parts is restored. Revitalizant itself can be used in all types of automatic transmissions, added to any oil, since the additive does not enter into chemical reactions and does not cause changes in viscosity, friction, or other physical and chemical properties of ATF.