How to eliminate grinding when changing gears? - undirbúningur fyrir endurnýjun hreyfilsins, gírkassa og annarra tækja

How to eliminate grinding when changing gears?

To understand where the problems with our manual transmission come from, it is first necessary to understand how it works. Thanks to the proper arrangement of the gears, we can usually use 5, 6 forward gears, which allow us to adjust the power to the requirements of driving. In addition, we also use reverse gear and the so-called. “slack”.

However, this whole mechanism does not work alone. An important role is played by small transmission components such as gear synchronizers that are responsible for smooth and quiet gear changes (without grinding) and gearbox bearings in which the gearbox shafts are embedded along with all modes.

Both of these elements are heavily loaded during the operation of the vehicle. Thus, they are exposed to wear, which may be manifested by noise, grinding – especially in the case of cars with mileage exceeding 100-150 thousand km.

Gearbox damage – causes

The causes of damage and wear of the gearbox can be many. The most common are:

  • Changing gears too fast.
  • Heavy load on the transmission at low revs.
  • Gearbox leaks and driving with too little oil in the gearbox.
  • Driving with overworked oil, not changing the oil in the gearbox.

Changing gears too fast

The gearbox is an extremely precise mechanism that requires a gentle smooth treatment. Dynamic “driving gears”, especially when the oil is still cold, leads to rapid wear of the synchronizers. Wear of synchronizers is manifested by grinding when changing gears.

Heavy gear loading at low revs

Heavy load on the gearbox at low rotational speeds results in bearing wear. In modern cars, especially modern ones, equipped with powerful diesel engines offering high torque from low revs, this is quite a common phenomenon. The car pleasantly accelerates from low revs, which encourages you to press the pedal into the floor at low revolutions of 1200-1500 rpm. Unfortunately, the gearbox bearings suffer from this.

Gearbox leaks

A small amount of oil enters the gearbox, most often from 1 to 2 liters of oil, hence even a small leak, after some time (1-2 years) can lead to a complete loss of oil. An underestimated oil level in the gearbox can manifest itself as difficulty changing gears – more resistance when trying to change gears.

gearbox leaks


Oil leaks from the gearbox can lead to its overheating and complete failure. They cannot be underestimated.

In most gearboxes there is no bayonet for oil level control, so any oil leaks from the gearbox should be eliminated as soon as possible – because it is very difficult to control the current oil level. In addition, in most cars there is no oil level sensor in the gearbox that could signal a low oil level with a red warning light.

The most common causes of leaks from the gearbox are semi-axle sealants and clutch shaft sealant. It is worth “sealing” the gearbox because oil leaks can lead to overheating of the transmission and, as a consequence, even to its damage, which may ultimately entail the need to carry out operations such as replacing the gearbox or repairing the gearbox.

Driving with used oil

It is well known that you need to regularly change the oil in the engine (we recommend changing every 10,000 km). In the case of the gearbox, unfortunately, the opinion that the transmission oil does not need to be replaced has been “accepted”. This is a mistake, because the oil, along with the passage of time and temperature loads to which it is subjected, undergoes oxidation and gradual degradation, which reduces its protective properties. Remember to change the oil in the gearbox every 100,000 km and if you do not have information about whether the oil in the gearbox has been changed – then prophylactically make a replacement and “for the future” write down the mileage at which you changed the oil.

gearbox oil

On the left side, new atf type transmission oil, on the right side oil with a mileage of 100 thousand. Miles.

Damage to the gearbox – symptoms

If you hear noise from the gearbox in the form of noise while driving, and the noise is heard in every gear (the noise deepens with the speed of the vehicle), we are probably dealing with noisy gearbox bearings.

If the noise occurs only when changing a specific gear (e.g. changing from gear 1 to 2) and is manifested by a grind, then the cause is probably a worn synchronizer of a given gear.

A ‘gearbox howl’ occurring only in certain gears and in a narrow engine speed range may in turn mean wear on the individual gears.

Grinding when changing gears

The most common cause of crunches during gear changes is a worn synchronizer. The synchronizer is designed to equalize the rotational speed of two modes that mesh with each other and is a kind of brake, thanks to which these two modes spinning at different speeds, adjust their rotational speed to each other – which allows their quiet meshing, without grinding.

Worn (worn-) synchronizers are responsible for the crunches during gear changes.


In a situation where the synchronizer is worn, its inner friction side no longer has such possibilities of braking and adjusting the modes to each other, as a result of which the gear modes overlap at different rotational speeds, which in turn leads to a grind when changing gears.

Driving with this fault may in the long run cause damage to the teeth of the gear modes (at which there are crunches) and the need to replace them.

Driving noise / howling

Driving noise is most often caused by worn gearbox bearings.

Their consumption is manifested by noise in the form of noise, deepening with the speed of the vehicle. Ignoring these symptoms over a longer period of time can manifest itself in cross-border bearing wear and “bearing bulk”, which can lead to incorrect meshing of the gears, including the rupture of the gearbox housing.

noise while driving

Gearbox regeneration

How to silence the bearings in the gearbox?

An effective method to silence gearbox bearings is to replace them. This process, however, requires dismantling the gearbox and almost completely disassembling it into the main components. By the way, prophylactic replacement of the semi-axle seals and clutch shaft and, of course, the oil is usually performed. Although the cost of the bearings themselves is usually not an excessive amount and can be purchased in the range of PLN 400-1000, their replacement together with the service of sealants can cost up to PLN 1500-2500.

How to mute the grind when changing gears?

To get rid of grinds when changing gears , you need to replace the synchronizers. In the case of replacing synchronizers, the situation is similar, the synchronizers themselves are not expensive (PLN 500-1000 set), but the replacement process itself – i.e. disassembling the gearbox, disassembling the gearbox, disassembling into component parts, replacing elements, assembling the box, changing oil on the occasion of oil, sealants costs ABOUT 1500-2500 PLN.

gearbox bearings

The cost of replacing bearings or synchronizers along with the service of removing and disassembling the gearbox is a cost of 1500-2500 PLN.


What are other alternative methods of gearbox regeneration?

Both replacement and regeneration of the gearbox are associated with significant costs, which most often exceed PLN 2000-2500.

It is worth taking an interest in an effective and tested addition to the gearbox with regenerating properties – which is Ceramizer CB.

The addition to the Ceramizer CB gearbox, performs
a double function. On the one hand , it regenerates the metal surfaces of the gearbox – especially synchronizers and bearings. It eliminates gearbox grinds and silences bearings. On the other hand, it acts prophylactically and creates a protective layer with more than 5 times greater wear resistance than the original coating.

Graphic example

Regeneration of the gearbox after the use of Ceramizers takes 1500 km.


Ceramizer CB fills worn places with a ceramic-metal layer. Quite unusual seems to be the lack of necessity to dismantle the mechanism. Regeneration of the gearbox is carried out without removing it, since repair processes take place during normal use. Thus, we do not have to worry about looking for a replacement car and we can save money. The regeneration process takes 1500 km from the moment the preparation is added to the transmission oil. The first effects can often be noticed after 500 km.

Ceramizer CB transmission oil additive – effectively eliminates grinds when changing gears and silences the transmission.


Unlike other oil additives, Ceramizer contains only 4 grams of active component, has been available on the market for over 15 years and its effectiveness is evidenced by 245 positive opinion pages. No other gearbox product has so many opinions.

Ceramizer is an addition to the silencing of the gearbox, it is especially effective in the case of wear of synchronizers that are manifested by grinding at the time of changing gears. The product reduces and in many cases even completely eliminates grinding. The product is also suitable for gearbox noise/noise, which is caused by moderate wear of the gearbox bearings.

Repair of the gearbox is a cost in the range of 2000-3000 PLN, while Ceramizer CB is an expense of only 66 PLN, so it is worth trying this method of gearbox regeneration, the more that it is a 100% safe product. Ceramizer CB – gearbox regenerator will significantly increase the smoothness when changing gears. In addition, the durability of the mechanism will increase up to 5 times, and the box will be protected against wear up to 100,000 km. However, it should be remembered that the regeneration of the gearbox applies to worn elements, not damaged ones.

Ceramizer and oil in the gearbox

To the question of what transmission oil should be used with Ceramizer, the answer is – everyone. Ceramizer can be used for any transmission oil.

Previous post
What additive will stop the engine from taking oil?
Next post
Is it worth using a rinse for the engine?

Leave a Reply

Your email address will not be published. Required fields are marked *