Gearbox maintenance
Auto Terms,  Car transmission,  Car device

Gearbox maintenance

For the proper operation of any car, each vehicle owner must not only monitor the occurrence of malfunctions of mechanisms, but also service them in time. To facilitate the task of determining the timing of each procedure, the automaker sets up a schedule for maintenance.

During scheduled maintenance, all components and assemblies are checked for faults. This procedure is designed to prevent emergency car breakdowns on the road. In the case of some mechanisms, this can lead to an accident. Consider the steps involved in servicing gearboxes.

Gearbox maintenance

Typically, vehicle maintenance falls into three categories:

  • First maintenance. At this point, most technical fluids and filters are replaced. The tightening of fasteners is checked on all mechanisms in which strong vibrations are generated. This category also includes gearboxes. Moving joints (hinges) are lubricated, and the ventilation holes are cleaned. The oil level in the crankcase is checked. For this, most car models have a special probe, similar to an analog for the engine. The bottom part is marked with a minimum and maximum level.
  • Second maintenance. The oil is changed in the box, the ventilation holes are cleaned. If the car is equipped with a transfer case, then the lubricant in it changes along with the gearbox oil. Replacement must be done after a short trip. This makes the oil more fluid, which makes it easier to drain from the crankcase.
  • Seasonal service. Although it is mainly drivers who change wheels in spring / autumn, you should pay attention to the recommendations for changing the lubricant. In most regions, the transmission is filled with multigrade oil. However, in northern regions, seasonal lubrication is required. In this case, with the transition to winter tires, the motorist must fill in winter lubricant, and in the spring, on the contrary, summer.

Routine vehicle maintenance occurs at regular intervals. The automaker itself sets the mileage through which work needs to be done. Usually TO-1 is carried out after 15 thousand, and TO-2 - 30 thousand kilometers from the starting point (for example, buying a new car, overhaul, etc.). Regardless of the vehicle, the lubricant level in the crankcase must be checked each time. If necessary (level close to the minimum value or below) oil is added.

Gearbox maintenance

When changing the lubricant in some units, the cavity must be flushed with a special oil. In this case, the manufacturer indicates how this procedure is carried out with each vehicle. Usually, the old grease is drained, the cavity is filled with a small amount of flushing material, the car starts up and runs at idle speed. After this procedure, the liquid is drained and new oil is poured.

If during the operation of the car there are any extraneous noises or vibrations from the transmission, you do not need to wait for the car to travel the required number of kilometers to check what the problem is. It is better to immediately take the vehicle for diagnostics or perform it yourself if you have experience in performing such procedures.

In addition to the scheduled inspection of the car, each driver should be attentive to the state of the box, regardless of whether it is a mechanical or automatic type (for more details about the types of vehicle transmission units, read here). When changing gears, the driver should not exert great effort. In the process of moving the lever of the box, there should be no clicks, knocks and other extraneous noise. Otherwise, you should immediately contact a mechanic for diagnosis.

Gearbox maintenance

During driving, the box should not heat up excessively. To make sure that the unit is working properly, it is enough to stop on the road and check the temperature by leaning your hand against the body. Ideally, the gearbox should be warm enough to rest your hand on it and not experience a scalding sensation. If the transmission heats up excessively, pay attention to the oil level.

Problems during the operation of the mechanical box

Basically, a manual transmission is the most reliable type of transmission among all modifications, so with proper care it will last a long time. The worst thing for such a gearbox is oil leakage from the crankcase. This can happen if the driver did not pay attention to oil drips, for example, at the installation site of the oil seals, as well as at the body joints.

Gearbox maintenance

If, after stopping the transport, even a small oil stain has formed under it, you should pay attention to the cause of the leak as soon as possible and eliminate it. Also, the driver should pay attention to whether the operation of the mechanism has changed: whether there are extraneous noises or more efforts need to be made to engage the gear.

As soon as a crunch or knock appeared, it is necessary to carry out the appropriate repairs, for example, replace the parts of the clutch basket or, in a more neglected case, the gears in the mechanism.

Consider what factors are critical for a manual transmission, and what causes them.

Difficult gear shifting

Gear shifting may require more effort in such cases:

  1. The clutch basket may not function well. Often, if this unit malfunctions, a strong crunch is heard when the speed is turned on. It is caused by the contact of the teeth of the gears in the box due to the fact that the pressure plate is not disconnected from the flywheel. As a result, even when the driver presses the clutch pedal, the drive shaft does not stop, but continues to rotate. This usually happens with a weak clutch cable tension.
  2. The shift fork is deformed. If it is not possible to eliminate the deformation, the part must be replaced.
  3. Synchronizers are worn out, due to which the rotation speed of the drive and driven shafts does not match. The result is gear slippage when the corresponding gear is engaged. Such a malfunction can only be eliminated by replacing the synchronizers. They are installed on the output shaft, so the driven shaft is removed for repair and disassembled.
  4. Cardan jamming. This usually happens with aggressive gear changes. If it is not possible to eliminate the scuffs with sandpaper (the part must be removed for this), then this element should be replaced with a new one.
  5. The fork rods move with great effort. If it is not possible to identify and eliminate the cause, the details are replaced with new ones.

Spontaneous shutdown or fuzzy engagement of gears

One of the characteristic faults of mechanics is that during driving, the included speed is automatically turned off. It also happens when the driver moves the lever to the third gear position, and the first is turned on (the same can happen with the fifth and third). Such situations are dangerous because in the first case it is a clear sign of a mechanism breakdown.

In the second situation, if nothing is done, the driver will break the box. When the gear shifts from fourth to fifth, the vehicle's speed is no longer consistent with third. If instead of the 5th, the 3rd turns on, then the car slows down sharply. In this case, the brake lights do not work, because the driver does not apply the brake. Naturally, the vehicle following from behind can "catch up" the car. But even on an empty road, inappropriate gear shifting will lead to overloading of the transmission and its imminent breakdown.

Gearbox maintenance

For some reason, the transmission may shut down on its own:

  • Locking rings on synchronizers are worn out. In this case, parts must be replaced.
  • The teeth on the synchronizer couplings are worn out. For repair, you will have to remove the secondary shaft and disassemble it.
  • The retainer of the shift fork is worn out or its spring has broken. When such a malfunction occurs, the spring ball retainer is replaced.

The gears can be switched on incorrectly due to the appearance of a development on the link hinge (for details on why a link is needed in the transmission, read separate article). Due to the backlash, the driver has to move the gearshift lever with a greater amplitude to the side. In some cases, in order to turn on the fifth gear, some have to move the lever literally under the foot of a passenger sitting next to it (a common phenomenon in many domestic cars).

Gearbox maintenance

To eliminate such a malfunction, you need to replace the cardan and adjust the rocker. Sometimes you can put an analogue from another car instead of a standard part. For example, some owners of VAZ 2108-99 throw out the factory hinge and put an analogue from Kalina instead.

Increased noise level

When the box makes a lot of noise during the movement of transport, this may indicate one of the following problems:

  1. The oil level in the box is below the minimum level. In this case, it is required to replenish the lack of volume of technical fluid, but before that, you should find out why it disappeared. If the machine is not equipped with a dipstick for checking the fluid level in the box (for example, the transmission for 2108 does not have such a part), then the reference point will be the filler hole, namely, its lower edge.
  2. Bearings worn out. If the reason for the noise is in them, then for safety they should be replaced.
  3. A worn synchronizer or gear has a similar effect. They also need to be replaced with serviceable ones.
  4. The shafts in the box move axially. This is due to the development in the bearings or backlash on their retainers. Apart from replacing defective parts, this backlash cannot be eliminated in any other way.

Oil leak

Gearbox maintenance

If oil drips appear under the box, and sometimes on its surface, you should pay attention to:

  • Sealing gaskets. They need to be replaced with new ones.
  • Box seals. In the process of installing a new cuff, the master could skew the part or did not use oil on the part through which the shaft is threaded, because of which its edge is wrapped or does not fit tightly to the contact surface of the part. If oil leakage occurs due to an incorrectly installed part, you need to contact another technician.
  • Fastening the pallet or parts of the box. If the gaskets have recently changed and a leak has appeared, check the bolt tightness.
  • Using the wrong gear oil. For example, a car needs mineral lubrication, and a motorist has filled in synthetics, which have a high fluidity, which can cause leakage even on a newly repaired mechanism.

How to change the oil in mechanics

Some modern car models do not need to change the transmission oil. These are mainly automatic boxes. Manufacturers fill in grease, the resource of which is identical to the period of operation of the automatic transmission. In mechanics, the lubricant must be changed. Previously, the replacement interval was within two to three thousand kilometers.

Gearbox maintenance

This was due to the quality of the lubricant as well as the stress on the mechanism. Today, thanks to innovative developments and all kinds of additives, this period has increased significantly.

Many mechanics recommend a preventive oil change after about 80 thousand kilometers. More information about which oil is best for the transmission is described in another review.

Gearbox maintenance

Although manual transmissions may have minor differences, the basic structure remains the same. Changing the transmission oil is also the same in each case. Here is the sequence in which it is carried out:

  • We prepare empty containers (the volume of the box is indicated in the technical documentation of the transport) for working off;
  • The lubrication changes after the trip, so if the car was stationary, you should drive a little before performing the procedure so that the liquid in the unit warms up;
  • We unscrew the drain plug;
  • The waste is discharged into an empty container;
  • Liquid mineral oil is poured (this step is needed for old domestic cars). Volume - approximately 0.7 liters;
  • We start the engine, let it run for about five minutes at idle speed and engaged in neutral;
  • We drain the grease (this flushing allows you to remove the residues of used oil from the crankcase, and with it small metal particles);
  • Fill in new grease according to the levels indicated on the dipstick.

After this work, the lubrication level must be checked when the car has traveled no more than 10 thousand kilometers. This should not be done immediately after the trip, as some of the fluid is retained on the gears and other parts of the mechanism. Better to let the car stand for a while. This will allow the grease to collect in the sump. If the volume needs to be replenished, use the same oil that was filled. For this, experienced motorists buy lubricant with a stock.

If a car with mechanics is bought on the secondary market, it is imperative to check whether the box is serviceable in such a vehicle. Here's a short video on how to do it:

We check the manual transmission on our own

Questions and answers:

What types of gearboxes are there? There are two fundamentally different boxes: mechanical and automatic. The second category includes: a variator (continuously variable transmission), a robot and an automatic machine.

What's inside the gearbox? Input shaft, output shaft, intermediate shaft, shift mechanism (gears), crankcase with drain plug. The robot has a double clutch, an automatic machine and a variator - a torque converter.

Which gearbox is more reliable? Classic automatic, because it is reliable, maintainable (affordable cost of repair and many knowledgeable specialists). It will provide more comfort than mechanics.

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