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, the hum almost certainly means death or the need for major repairs - stretching of 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?
