Noises in the gearbox: causes and troubleshooting options

Why does a manual transmission howl?

Many manual transmissions, even in good condition, are not very quiet. Even on a new car, the transmission can make sounds while driving, this is especially true for vehicles in the budget segment. For example, the whine of a VAZ gearbox is the norm for many cars. Every owner knows what the normal noise level is inside his car, and will always notice changes. If the noise of the box changes in tone, competes in volume with the sound of the engine, or appears in some specific conditions, you need to think about a visit to a car service center.

Many people confuse noise in the box with malfunctions of other elements. Often, while driving, a worn-out release bearing howls. The volume and tone of the noise directly depends on the speed of movement, so the diagnosis of “box whine” is mistakenly made. A clutch that requires replacement can also cause a similar problem. Without diagnostics, it is difficult to figure out what causes the unpleasant sound, so it is better to contact a car repair shop.

If the manual transmission itself makes a hum, there may be several reasons:

• If there is insufficient lubrication, a hum may occur due to intense friction of parts. The howl is heard especially clearly in higher gears.
• Noise may occur after improper repair of the gearbox. Assembly requires precision. If the shafts and gears are misaligned relative to each other, the box will make noise.
• A common cause of noise is failure of synchronizers. This malfunction is usually accompanied by a grinding noise when engaging certain gears.
• If the noise is present when the gear selector is in neutral, there is likely a problem with the input shaft bearing.
• The pinion bearing may also make a noise.
• Wear of the main pair is another source of box howling. If measures are not taken in time, other parts will also fail.
• If the whine is only heard in a certain gear, the cause lies in the gears. If their teeth are damaged, the box will hum.
• If the box hums when cold, especially in the winter, the culprit may be that the oil is too thick. After warming up, the transmission is much quieter.
• Old oil in a box may contain metal shavings and other impurities. This may be the cause of the noise.

If a howl appears in the box, pay attention when it occurs, whether its pitch and volume changes in different modes. If noise appears when the clutch is depressed, there is a crunching sound when engaging 1st or 2nd gears, there is a high probability of wear of the release bearing. Extraneous sounds when engaging certain gears indicate problems with gears or synchronizers. A humming noise in higher gears or in cold gears may indicate an insufficient level or low quality of transmission oil.

How to prevent gearbox failure

Early signs of future failure include:

1. Difficulties appearing when changing gears. It becomes more and more difficult to change gears. Sometimes you have to squeeze the clutch and move the lever to neutral.
2. The transmissions are flying out.
3. Oil is leaking from the gearbox.

Bearing wear
Another common cause of problems during gear shifting is due to improper adjustment of the shift drive. Assembly parts often break and can also cause the problem. To eliminate problems, it is necessary to correct or replace the rod as soon as possible, as well as tighten the screws. Then you can start adjusting the drive and replacing the remaining non-functioning parts.

On some VAZ 2114 vehicles, a gear reset occurs. This process occurs spontaneously. The reason is wear or breakage of the teeth (end teeth) on the coupling. Sometimes the teeth on the gears fail. A similar problem arises due to insufficiently competent debugging of the drive. In other cases, the reason lies in inaccuracy during the installation of the traction cover, which is intended for protection.

To correct this problem, you may need to replace all faulty parts. Next you should start debugging the drive.

The next step is to install the cover in the required position. If an oil leak occurs, then it is necessary to install the crankcase and change any gaskets that look worn out. Do not forget about the need to remove the box before repairing.

The howl of an automatic transmission, robot or variator

Automatic transmissions are normally quieter than manual transmissions. If the howl of a manual Niva or Lada Kalina transmission may be a normal condition of the transmission, then third-party sounds from the automatic transmission should alert the car owner. Diagnosing the causes of third-party sounds when operating automatic transmissions is quite difficult. Sometimes computer diagnostics can help identify the problem, but in most cases you have to remove and disassemble the transmission. Having learned the cost of this procedure, many continue to drive a car and drown out the howling with loud music. But this is wrong; with significant wear of all internal components, repairs will cost more than with minor problems. In addition, a faulty transmission can fail at any time.

The main reasons for howling automatic transmission:

• If there is little transmission fluid in the box, usually not only extraneous sounds appear, but also kicks when changing gears.
• If the automatic transmission starts to howl after repair, it may have been assembled incorrectly. Even a slight displacement of parts leads to the appearance of third-party sounds.
• If the axle shafts are poorly secured, play occurs, which leads to noise.
• The quality of the transmission fluid also affects the operation of the automatic transmission. If the oil is old, contains mechanical impurities, or a fluid that does not meet the manufacturer’s requirements is filled in, the box will begin to hum.
• Worn or damaged gears, bearings and other mechanical parts lead to the appearance of extraneous sounds.

An automatic transmission is a rather complex mechanism compared to a manual transmission, which is why it is more difficult to identify the cause of the howling. But even if you need to disassemble the transmission with troubleshooting, it is better to perform this procedure than to face a critical breakdown along the way.

Let's sum it up

Many motorists are faced with such a problem as gearbox noise. It could be an automatic or manual transmission, any version of a modern robot or such a fashionable CVT. There are dozens of diseases of technical components and assemblies that can negatively affect this part of your car. Therefore, you should pay special attention to the features that the gearbox provides you during operation. If you simply miss the moment when bearings or other parts begin to hum, you may soon find yourself on the side of the road without the ability to move in your car.

There are many types of motorists. Some people want their vehicle to work perfectly, others are content with the fact that as long as the car is driving, there is no need 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 the unpleasant hum. Most likely, after such diagnostics, you will want to restore the node. Has your car ever had problems with the gearbox that caused an unpleasant hum?

What to do if the box howls

The first thing a car owner should think about when a howling noise appears in the transmission is a transmission fluid leak. Inspect the car's riser for oil stains, assess the oil level in the box using the dipstick, which most car models have. If the transmission fluid level is below the minimum mark, it must be topped up immediately. Use only the brand of oil that comes in the box. You cannot mix liquids from different manufacturers. You should know that automatic transmissions are very sensitive to the level of lubrication, so an overflow of transmission fluid is as unacceptable as a lack of it. If the oil has not been changed for a long time, it should be done. Automatic transmissions are especially sensitive to the quality of transmission fluid.

If it was not possible to eliminate the howling of the box by replacing or adding oil, you need to go to a service station for diagnostics. Specialists will assess the condition of the transmission and tell you how much repair is needed.

If you decide to sort through the box, you should take into account that the cost of such work is quite high. That is why it is advisable to purchase new original spare parts. Only in this case can you count on a long service life of the transmission after repair. Buying used spare parts or cheap parts from a dubious manufacturer is an imaginary savings. There is a high probability that soon after such repairs the gearbox will have to be disassembled again.

If the main pair is damaged, it is rarely possible to get by only by replacing it. Usually in such a situation other parts also suffer, so you need to evaluate their condition and, if necessary, also replace them.

Sometimes repairing a box turns out to be very difficult and expensive. In this case, it is advisable to replace the entire transmission. You can buy a new unit or find a used box in working condition.

Should I use additives?

There are special additives for gearboxes. Is it worth using them, will they solve the problem of transmission whining?

Additives are effective in preventing breakdowns. Many of them can significantly increase the service life of the transmission. If a minor malfunction occurs, using these products will help temporarily get rid of the noise and delay repair time. But you shouldn’t hope to restore the parts; sooner or later they will have to be replaced anyway.

If the box is severely worn, and even more so if it fails, additives are ineffective. In this case, you shouldn’t spend money on auto chemicals; it’s better to go straight to the service center.

Additives for automatic and manual transmissions differ in their properties. Use automotive chemicals designed for the type of transmission installed in your vehicle. Avoid using products from dubious manufacturers. At best, they will have no effect, and at worst, they will lead to more serious problems.

Symptoms of manual transmission malfunctions

Many drivers unknowingly confuse the symptoms of a manual transmission malfunction with signs of a breakdown in the gear selection mechanism or clutch. Fortunately, manual transmissions require much less attention than automatic transmissions, CVTs, DSG and robotic gearboxes. But even highly reliable units eventually begin to make noise at idle, while driving, and suffer from poor gear shifting.

conclusions

The howling of a Renault, Lada Vesta, Grant or any other car is a problem that cannot be ignored. A working transmission does not make any strange sounds, so if they appear, go to a service center as soon as possible. The sooner the diagnosis is carried out, the cheaper the repair will cost. If you constantly postpone this event, then the howl may end in buying a new box.

The gearbox is a rather complex unit, especially when it comes to an automatic transmission. Do not trust repairs and diagnostics to random people. It is better to contact a specialized auto repair shop that has the necessary equipment and tools.

VAZ checkpoint, a frequent source of howling.

Worn synchronizers are a source of increased noise. For replacement.

A worn input shaft bearing is another enemy of silence.

A faulty release bearing is a frequent source of additional noise.

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