Howl manual transmission. Hum in the gearbox: causes and possible consequences

The gearbox is one of the most complex mechanisms in the entire car. Only the engine can compete with it in terms of design complexity. This is the reason why it is often even more expensive to repair a box than a power unit. To understand all the features of this process, it is enough to consider the gearbox diagrams from the inside - this will give an understanding of the high complexity and manufacturability of all the mechanisms built into the housing. Repairs must be carried out exclusively by a professional, otherwise the unit will not be able to pass a sufficient amount of time. You need to understand that the reliability of the car’s trip, the convenience of its operation and the physical ability to go on long journeys without fear of terrible breakdowns depend on the quality of the box.

The box can show a variety of troubles during operation, but one of the most common manifestations of a breakdown is a rumble in the gearbox. The hum can be of different intensity, tone and strength. You can barely notice it, and sometimes the rumble is such that you simply don’t want to accelerate the car to high speed or turn the engine to high speeds. Sometimes such a hum turns out to be only evidence of some technological feature of the box. Sometimes it occurs after repair, when the parts do not fully fit together. In this case, this is not critical, but the hum can be removed only with the help of repeated repairs. Let's look at the reasons that make you feel increasing discomfort when driving in a car and feel unpleasant sounds from under the hood.

Automatic gearbox - the hum is definitely not good

If you have an automatic transmission, CVT or robotic mechanics with automatic shifting, the hum definitely does not bode well for you. At any service, just disassembling and assembling your box will cost fabulous money. Today, you will not be too pleased with the prices for spare parts. Sometimes it is better to listen to the hum than to hear the price that is required to eliminate it. Use the help of specialists to diagnose the gearbox, but remember that a complete diagnosis of your machine is possible only if the box is disassembled. The most common causes of automatic transmission noise are:

• in a conventional machine or in a robotic box, one of the elements of the main pair can be erased, giving backlash in work;
• the gears do not hit each other in normal modes, there is excessive friction of the mechanisms in the box;
• for a variator, a hum almost certainly means death or the need for a major overhaul - stretching the main working mechanisms is not so rare;
• also, the box may hum due to poor fastening of the axle shafts, which causes play at the junctions and a rather strong hum;
• bearings that are out of order often buzz, they will definitely show themselves in the near future;
• worn teeth on the drive gear or on the shaft will indicate the presence of play and a constant hum in one or more gears.

Often, along with the hum, some other troubles with the gearbox begin to occur. For example, the gearbox starts to throw out one of the gears after you release the gas pedal to slow down. Gear forks may be to blame for this, but it all depends on the box, its type, design and other features. If for mechanics such a problem is quite simple to manage, then for an automatic transmission, dropping gears in unauthorized mode means the impossibility of operating the car. Otherwise, driving such a car will be unsafe. So always keep an eye on the sounds appearing from the machine and contact the service center to eliminate them.

Manual transmissions - hum for many reasons

In mechanics, the causes of hum in gearboxes are no less than in automatic ones. It must be remembered that the mechanical box is quite gentle, likes moderate operation and the absence of sudden movements. This even applies to sports boxes, which are the most protected against damage in sporty driving conditions. However, such boxes are considered more reliable and durable than automatic types. This is a rather controversial truth, because there are different machines and there are various manual transmissions. Many motorists prefer mechanics due to the rather low cost of restoration. Although, it depends on what caused the hum in the gearbox:

• wear or unequal replacement of the elements of the main pair - the hum can last for a long time without negative consequences, but, in the end, the box will fail;
• the drive bearings are worn out - they will buzz for several weeks of active operation and fall apart, causing not very pleasant consequences;
• gears of gears - if the rumble is heard in only one gear, the culprit of such a nuisance is the gear of this particular gear;
• poor-quality assembly of the box is often the reason that there is a hum due to a mismatch between the shaft and the gears;
• poor operation of the gear engagement mechanism leads to the fact that the inclusions are inaccurate and uneven;
• often there are individual and unforeseen problems in mechanical boxes, which are diagnosed only after disassembly.

Such troubles are possible in every car. Of course, domestic cars are becoming more frequent visitors to professional service stations. But often expensive high-tech foreign cars come to the station with questions about the hum of the gearbox. It should be noted that in most cases high-end cars do not present such problems. They are made of the highest quality and can last for many years without question. But in some cases, it is not the engineer or assembler at the factory who is responsible for the breakdown of the box, but the driver himself.

What to do if a rumble begins to come out of the box?

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

• bring the car to a quality service with a sufficiently large number of specialists and good equipment for repair;
• order for starters disassembly and full detailed diagnostics of the gearbox to identify problems;
• when identifying a problem, estimate the cost of restoring the machine and potentially repairing your box;
• make a decision based on the proposed facts and the information provided by the experts;
• order gearbox repair to those professionals whom you completely trust - poor quality of repairs cannot be allowed;
• 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 gearbox repair is disassembly and diagnostics. Then everything is done at affordable rates SRT. You need to keep this in mind when choosing parts for your gearbox. It is best to use the original factory spare parts options to completely eliminate trouble in the near future. So you save on subsequent repairs and can easily complete the necessary tasks in one process of disassembling the box. You should not save on details and on the quality of work performed, as this may adversely affect the operation of the unit. We propose to consider the causes of the hum in the box, which experts say:

Summing up

Many motorists are faced with such a problem as the rumble of the gearbox. It can be automatic or manual, every variant of a modern robot or such a fashionable variator. There are dozens of diseases of technical components and assemblies that can adversely affect this part of your car's equipment. Therefore, you should pay special attention to the features that the gearbox provides you with during operation. If you simply miss the moment the bearings or other parts begin to hum, you may soon find yourself at the curb of the road without the ability to move in the car.

There are many types of motorists. Some want the perfect performance of their vehicle, others are content with the fact that while the car is running, there is nothing to repair it. But most vehicle owners want the main components of the car to work well and efficiently. Therefore, do not neglect good diagnostics to find out which part of the box is causing an unpleasant hum. Most likely, after such a diagnosis, you will want to restore the node. Has your car had problems with the gearbox that caused an unpleasant hum?

Reading 6 min.

Gearbox whine is a fairly common occurrence. How to correctly diagnose problems and decide on the need for repair.

Oil: could it be the reason?

There are several reasons why the gearbox starts to howl. The first, most common, is the oil level in the box. Many motorists do not attach importance to the need to control the oil level in the gearbox. This leads to oil starvation in the fifth gear, which is higher than the rest. Due to the lack of oil, the bearings begin to overheat and fail. This is accompanied by a high-pitched howl that occurs when driving in fifth gear. Such a disease is treated by overflowing 100 - 200 grams of gear oil above the level with its constant monitoring.

Some may say that overfilling the oil will cause it to leak through the seals. To prevent this from happening, it is necessary first of all to clean the breather, and secondly, pour the oil in parts, gradually. For example, first 100 grams, and after a while, in the absence of a leak, so much more. You can also add a second oil seal to the gearbox link.

The next, no less common reason for the sound of the gearbox is the poor quality of the transmission oil poured into the gearbox or incorrectly selected. If we talk about domestic cars, then, for example, the use of oils of the APIGL-5 category in the gearbox of front-wheel drive VAZs leads to rapid wear of the synchronizers, which will cause the noise of the box when switching. Therefore, the use of an APIGL-4 class transmission is mandatory. Domestic oils of this classification are quite difficult to find, so foreign manufacturers have to use lubricants. But their use can significantly extend the life of the gearbox, avoiding various sounds when driving.

In addition, insufficient or excessive viscosity of the oil used also affects the wear of the box parts and the presence of sound during its operation. So, for example, a very thick oil with a viscosity of 85W-90 creates a strong film, protecting gears from wear, but at the same time, lubricant access to some parts of the box is difficult, which may suffer from oil starvation, failing prematurely. It will also be difficult to shift gears due to the need for synchronizers to squeeze out excess oil, which again will lead to rapid wear of parts. The first sign of a very thick oil will be the presence of a howl on a cold one and its disappearance on a warm unit.

Too thin oil will cause the opposite effect, in which the oil film will break off when hot, accelerating the wear of gearbox parts, which will again be accompanied by a howl and hum.

You should be extremely careful in choosing gear oil according to the recommendations of the manufacturer and experienced servicemen.

Oil additives: is it possible to do without repair?

If an oil change does not help, the gearbox howls, then it is necessary to repair the unit. Many people may say about adding additives, but this does not help in 80 percent of cases. According to the reviews of many motorists, the addition of additives can only temporarily or not completely muffle the sound, but it will not completely solve the problem.

Chemically active substances contained in revitalizing additives form a ceramic-metal layer on the surface of worn gears and bearings, which, according to the manufacturer, restores the geometry of parts and compensates for wear. Of course, if the howl of the gearbox is barely audible, it has just begun, then adding, for example, Hado, may well delay the problem with the repair of the gearbox. But it may not help if the problem is already old, and the wear of the units of the unit is significant. Then a repair is definitely needed.

Diagnostics and repair

As for the repair of the gearbox, it is very important to start by correctly diagnosing a possible malfunction of the unit, to try to determine why the box emits a howl without removing the unit. Usually the box howls not in all modes, but at some speeds. If a howl accompanies movement in 1,2,3 gears, then this usually indicates problems with the bearing connecting the primary and secondary shafts, more precisely, its wear. The only way out is to replace it. But there is a small nuance - if the bearing is a needle bearing that does not have a cage, then simply replacing the needles may not help. This will require replacement shafts. And this is a serious renovation.

It is also possible to have a howl when the working pair of gears located on the primary and secondary shafts of these gears is worn out. Or with poor-quality factory processing and installation after repair. One of the hallmarks of gear wear is howling under load and decreasing when there is no traction. A worn bearing will make noise in any case - there is a load or not. But you can determine exactly the reasons only by disassembling the gearbox, showing the specialist if the repair is done by yourself.

If there is a howl in 5th gear, the first thing to do is to check and add oil to the unit if necessary, as already mentioned earlier. But if this does not help, then it is most likely that the fifth gear needs to be replaced. This is determined by opening the box. Previously, by sound at high speed, you can determine the cause - with a frank howl, the gear is worn out, with a squeak of more than 100 km / h - most likely, the bearing.

If the box of front-wheel drive cars howls in all gears, then there is a high probability of wear on the input shaft bearing. But replacing it often does not lead to a positive result, so changing it in the presence of a slight howl is not recommended.

Or maybe it's not a box at all?

When diagnosing a gearbox, be sure to carefully consider the fact that in the presence of an ever-increasing howl in all gears, not only the gearbox can be guilty of the origin of sounds. On models with a classic drive, the source of the howl may be the rear axle gearbox, which has a bevel hypoid gear. With wear of the gear teeth or with a significant play of the bearings, the howl will accompany all modes of movement. Similar symptoms also accompany an all-wheel drive vehicle in the event of a front axle malfunction. In this case, the sound will come from the center of the cabin, and be observed under loads.

Summing up

When repairing a singing gearbox, it is important to remember the poor quality of manufactured units and spare parts. It is not indicative that the purchased spare parts or units are new - there may be defects in them. Sometimes, with minor noises in the gearbox, it is easier to add the sound of the radio in the cabin than trying to eliminate the cricket several times to sort out the box.

Good luck on the roads!

Probably, almost every motorist was faced with the fact that the gearbox of the car began to howl. VAZ-2114 is no exception in this case, and even such a “simple” car can have such an unpleasant effect. But, not everyone knows what causes this problem. In this article, we will consider the causes of howling in the checkpoint and methods for eliminating the effect.

The consequences of the howl of the checkpoint on the video. Gearbox from VAZ-2114:

General view of the gearbox

Before proceeding directly to the issue of considering the appearance of noise in the gearbox, it is necessary to consider the design features of the VAZ-2114 gearbox. So, what parts does this assembly consist of.

Gearbox diagram

Gearbox: 1 - clutch release bearing; 2 - guide sleeve; 3 - input shaft; 4 - roller bearing of the secondary shaft; 5 - secondary shaft; 6 - retaining ring; 7 - the axis of the satellites; 8 – a driving gear wheel of a drive of a speedometer; 9 - transport cap; 10 – an epiploon of a drive of a wheel; 11 - roller tapered differential bearing; 12 - half shaft gear; 13 - satellite; 14 - differential box; 15 - clutch housing; 16 - driven gear of the main gear; 17 - drain plug; 18 - adjusting ring; 19 - driven gear of the 1st gear of the secondary shaft; 20 - synchronizer of I and II gears as an assembly; 21 - driven gear of the second gear of the secondary shaft; 22 - retaining ring; 23 - persistent half ring; 24 - driven gear of the third gear of the secondary shaft; 25 - synchronizer III and IV gear assembly; 26 - driven gear of the fourth gear of the secondary shaft; 27 - needle bearing gears of the secondary shaft; 28 - ball bearing of the secondary shaft; 29 - thrust plate; 30 - driven gear of the V transmission of the secondary shaft; 31 - synchronizer V transmission assembly; 32 - nut; 33 - thrust washer; 34 - drive gear of the V transmission of the input shaft; 35 – a back cover of a case of a transmission; 36 - ball bearing input shaft; 37 - gearbox housing; 38 - roller bearing input shaft; 39 - breather; 40 - input shaft seal

Causes of the malfunction

When the design of the gearbox is understood, one can proceed directly to the consideration of all possible causes of the effect. According to the manufacturer's data indicated in the regulatory literature and practice of motorists, it is possible to distinguish such factors that lead to howling of the gearbox:

• Worn gears, namely the teeth of the part.
• Shaft bearing failure.
• Low oil level.

Now you can go directly to the troubleshooting methods.

Howling box - elimination methods

So, when the causes are known, the issue of methods of elimination can be considered. If you look at the causes, you can logically guess how to troubleshoot. But, it is worth considering this issue in more detail.

Gear wear on gearbox

The process of disassembling and diagnosing gearbox gears

The teeth of the gears wear out due to the fact that the driver engages the clutch incorrectly or tries to shift into gear without it.

Also, the cause of wear may be that the oil level in the gearbox is insufficient, or it has lost its physical and chemical properties. So, you will have to dismantle the entire assembly, as well as sort out the gearbox completely, since the gears are located on both shafts.

Bearing wear

Dismantling and inspection of the gearbox needle bearings

Bearings wear out during operation. Their replacement will require the dismantling of all internal elements. So, it will be necessary to dismantle the gearbox, as well as make a complete bulkhead.

Fifth gear needle bearing crumbled

The replacement of elements is quite simple if the gearbox is removed from the car.

Lack of oil

Checking the oil level with a dipstick

Lack of oil in the gearbox can lead to increased wear of internal components and assemblies.

The probe must be inserted carefully so as not to damage it. The rest of the metal from the probe will remain in the box

So, topping up the lubricant can remove this effect. Although, as practice shows, it is best to drain the old oil and fill in new oil in order to completely and completely remove the noise in the box.

Video about why the gearbox howls

conclusions

The howl of the VAZ-2114 gearbox has several reasons that are not so easy to diagnose. In order to determine the breakdown, you will have to dismantle the assembly, as well as disassemble it, which is not possible for every motorist. If the owner is not able to do it himself, then it is recommended to contact a car service where they will fix the problem.

I think no one will argue that any gearbox is one of the most key parts in a car. Therefore, all the problems that sooner or later arise with the checkpoint must be eliminated in time. 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.

Sectional view of a manual transmission

During operation, the box can demonstrate various troubles that stand out not only with the characteristic sound. But, in today's example, let's take the hum as a basis, what problems can it indicate and what consequences can the car owner expect?

Interestingly, howling can be completely different, different from traffic intensity, speed, gear engaged, and the like, but its signs usually come down to one list of problems.

By the way, it may not always indicate that there are problems with the checkpoint. It is quite real that this is a design feature of a particular mechanism, or the device has just been repaired, that is, the details have not yet got used. 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 loosened, the release bearing has worn out, etc.

Hum on the "mechanics"

The mechanical box is very widespread, structurally having a not very complex system, however, there are enough reasons why noise can be heard.

What is the MKPP made of?

For example, the position of the box in neutral, with the clutch depressed, a howl is heard, the reason for this in most cases is a worn input shaft bearing or a drive gear bearing. The same thing, when you release the clutch and noise is heard, it's all about the input shaft bearing.

In the photo: the remains of the bearing in the input shaft. Photo — drive2.ru

In general, there can be many reasons for causing extraneous sounds, even for "mechanics":

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

in the photo: GAZ 21 manual transmission gear

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

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

Oil starvation. Few people pay attention to the oil level in the box, but this is an important indicator. If the oil falls below the mark, a sound will be heard in certain gears.

Checking the oil in a manual transmission Hyundai i30

Often, the fifth gear, which is above all, suffers from an insufficient amount of lubricating fluid.

Too thick oil. With a high degree of viscosity, the oil creates, like a protective film on the parts, which makes it difficult for lubricant to access certain parts. By the way, one of the signs that too thick oil is used is the presence of a hum on the “cold” one, after warming up, which disappears.

The oil is of poor quality and needs to be replaced. Used oil, possibly mixed with metal particles and water.

Shavings on the magnet of the gearbox drain plug

Wear of synchronizers or blocking rings on the shaft.

In the photo: synchronizer ring

Problems with the "fork" of the checkpoint. In this case, it is not uncommon to "" transfer.

By the way, if noise is heard during gear shifting, then you should pay attention first of all to the clutch, there may be problems with. Precisely, problems with the clutch release will be indicated by the fact that when squeezing, that is, when you press on, a rustle is heard. But, if on the contrary, when you release the pedal and noise is heard, then almost certainly there are problems with the box itself.

Also, the wear of the shifter will be indicated by the fact that the gears are not switched on accurately or with noticeable noise, a crunch, this is especially evident in the first and second gears.

In addition, the reason may be hiding in the synchronizers. Check the wear of the synchronizer parts, blocking rings, and also measure the gap between the gear and the blocking ring. In different models of the box, the data may differ, read the manual.

The hum of automatic transmission, robot or variator

The constructive part of such boxes is much more technologically advanced, therefore much more attention is paid to problems with them. It is often difficult to identify a malfunction without disassembling the assembly completely; even specialists using computer diagnostics will not really be able to identify problems. As a rule, a complete or partial analysis of the node is required, with live diagnostics. In view of which, many motorists try to ignore the howl, which in the end still results in expensive repairs. Here are just a small part of the reasons why a hum may occur at these checkpoints:

Similarly, the main shaft pair has worn out.

Poor fastening of the axle shafts, which may cause even a small backlash.

Excessive friction of parts, in particular gears due to displacement during installation or after repair.

Shaft bearings, gears failed.

Worn gears, worn teeth, wear on the shaft, all this leads to the appearance of various sounds.

The level of liquid, its quality does not meet the regulated standards of the manufacturer.

In the photo: automatic transmission without a sump, dismantling the oil filter

What to do if there is a hum?

In any case, from the listed reasons it is clear that the problems can be quite serious and lead to expensive repairs, so you should not neglect such a “signal”. You will need the help of a specialist, you can’t get away from this, because it’s difficult for a person who is not familiar with the mechanism to determine the problem on their own with 100% accuracy.

I would like to give some important tips during the diagnosis of the checkpoint:

1. Find out what exactly caused the howl to appear, if it is the shaft of the main pair, then keep in mind that it has already had its effect on other parts of the mechanism. Therefore, it is likely that only it cannot be replaced.

2. Think about the feasibility of repair, perhaps the cost of buying new or used parts will be large. Then it’s easier to find a contract gearbox or a used one, but in good condition, than to repair a “dead man”.

3. Stopped for repairs, buy only high-quality and original parts, this will extend the life of your car.

Conclusion

As a result, I would like to emphasize the main thing, do not neglect all kinds of signals that can come from the checkpoint, in the form of howling, knocking or special markings on the “tidy”. Ultimately, repairs can be much more expensive.

In addition, trust the diagnostics, and, accordingly, the disassembly of the box only to certified or proven services, avoid the so-called "garage" masters, from whom you can only get a new "portion" of problems.