design features of the gearbox of cars VAZ 2108, VAZ 2109, VAZ 21099

The gearbox, in any car, is responsible for increasing and decreasing the speed of the drive wheels, at the same number of crankshaft revolutions. The engine itself is not powerful enough, and its normal operating range (without increased wear) ranges from 1500 to 4000 rpm. Therefore, in order for the engine to have different speeds at a given speed, the car uses a gearbox (gearbox).

By type, boxes are divided into 2 types - mechanical and automatic. In this article, we will talk specifically about the mechanics of a VAZ 2108 car.

VAZ 2108 – gearbox: arrangement of components, its repair and improvement

The domestic car is a car with front-wheel drive, and the engine is placed transversely and is used for driving along the highways. The metal body is made in accordance with the hatchback type, which has 3 doors. The rear door is designed for loading and unloading luggage. When transporting long and oversized luggage, the rear row folds down - this increases the luggage compartment.

4-cylinder carburetor engines with a volume of 1.1, 1.3 or 1.5 liters. At the moment, fuel injection systems are installed in some cars. The front-wheel drive car guarantees improved vehicle handling when cornering, even on wet roads. During long-term use of the car, wear of many elements occurs, the fasteners of the assembly components are weakened and the adjustable values are violated.

The gearbox is the most reliable element in the car. Failure of this mechanism is quite rare compared to other parts. And with all this, its complete or partial failure makes the car completely unsuitable for further use. It will simply be impossible to operate the car for its intended purpose. In addition, you will need a tow truck to deliver the car for gearbox repair.

About the oil

For good performance of the VAZ 2109, all important components must be coated with oil. Typically, the manufacturer independently determines the brand of engine and transmission parts that are recommended for use in cars of a given model.

If you do not have such information, you should consider the main purpose of the machine:

if the VAZ is driven on excellent roads in the regional center, there is a certain type of oil for this;
if you drive a car, a transmission would be the ideal option.

Remember to maintain the optimal oil level

When filling oil, it should be taken into account that the VAZ 2109 box requires a slightly larger amount. Only this approach will help protect and cover all spare parts located at the crankcase outlet.

Since the gearbox is the second most important element of a car, in the event of the slightest breakdown it is necessary to immediately eliminate the shortcomings. Let's look at the main malfunctions that can occur with the gearbox

Let's look at the main malfunctions that can occur with the gearbox.

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Automatic transmission shutdown

worn gears and locks on the coupling;
failure to comply with vehicle operating rules;
incorrectly selected speed mode;
incorrect shifting with a poorly adjusted clutch;
unprofessional gearbox repair (ignoring clutch replacement);
ignoring repairs in the presence of extraneous noise in the form of crunching.

If you contact a service station in a timely manner, the VAZ gearbox can somehow be saved. If the condition is too neglected, count on expensive repairs.

What do the noises in the 2109 box mean?

There are no silent boxes. Each of them has a maximum permissible noise level, which is established by GOST.

Extraneous noise from the VAZ box may occur as a result of the operation of gears and bearings;
Used or low-quality oil also causes noise;
Sometimes the reason for its appearance may be the operation of the power unit. In this case, the speed may be unstable or a powerful camshaft may be installed.

It takes forever to describe extraneous noises, since each driver hears them differently. To more fully understand the cause, it is necessary to diagnose the transmission.

Crunching sound when changing gear

Excessive or improper use of the vehicle.

If there is a crunching noise, the synchronizer will need to be replaced. If you decide to save money on it, you should expect to buy a whole block of gears in the future.

In addition, the presence of a crunching sound may indicate that it is time to change the used oil. Or perhaps it was filled with the wrong degree of viscosity?

Knocks

If you hear knocking noises in 21099, you should immediately check the gears

Perhaps one of the pairs has a chip; If a knocking noise occurs while driving, or when you switch the gearbox from one gear to another, pay attention to the satellites. Most likely they are the ones that have worn out.

The gearbox on a VAZ burst

Whether or not to purchase a new box is up to you. Judge for yourself, repairing it can cost you the same price as buying a new one.

The box is unstable and switches hard

The cause of this type of problem with box 21099 is the synchronizer or gear. In some cases, this situation may occur when purchasing new gearboxes or after repairing them.

Gearbox synchronizer

In any case, you should know that when buying a new car you need to run it in. Rough operation of the vehicle leads to serious problems.

Predominant types of breakdowns

One of the types of gearbox failures on the VAZ 2108 is considered to be bearing wear or lack of oil in the gear shift unit. And with all this, this damage is very easy to fix by changing the oil or replacing the bearings. It is completely different if we are talking about more serious breakdowns associated with axial rearrangement of shafts, bending of the gearbox handle, jamming, unreasonable inclusion, disabling of gears, wear of fasteners, various nuts, as well as springs due to deterioration of the flexibility of balls - in such situations, without a full repair, it is not possible make do.

Construction design and further repair of the gearbox

Repairing a VAZ 2108 gearbox is a very complex and time-consuming process, especially if the car has sufficient mileage. Despite multiple service stations, not all specialists will be able to make repairs. There can be many reasons for this. For example, there is little experience, as well as a lack of spare parts in stock. The gearbox is considered a complex element of the car. It is capable of changing the traction force of the driving wheels of a car due to the engagement of gears with different numbers of teeth.

In addition, it provides reverse gear and long-term disconnection of the engine (together with the clutch) from other elements of the transmission, while the car is stationary or moving forward by inertia. The engagement of gears with different numbers of teeth is realized by their movement. The drive shaft is connected to the clutch disc, while the driven shaft is connected to other transmission elements.

The driven shaft, in relation to the main one, is capable of rotating with a different number of revolutions. The transition shaft with a fixed set of gears through them is in constant engagement with the main shaft.

Noise

Each box has its own noise limit, which is not a symptom of a malfunction. The transmission has gears that constantly rub against each other. And no matter how technologically advanced the design is, it is impossible to completely eliminate sound. As for the 5th gearbox VAZ-2109, its noise regulation is 78 dB. Anything higher is equivalent to a malfunction. And the box may make noise due to insufficient oil level in the box. As you know, gear oil has a higher viscosity than motor oil. And it is not sprayed by the pump. This oil is located in the gearbox housing. When the gear rotates, it dips itself into the lubricant. If the liquid level is below the permissible level, the element will run dry. This entails increased gear wear and wear. As a result, even if the oil level is restored, the problem will not disappear.

Noisiness also occurs due to increased loads on the box itself. This happens after tuning the engine (for example, installing “evil” camshafts), which the owners of “nines” love so much. As a result, the engine never drops below three thousand rpm. Both the engine and gearbox suffer wear and tear.

The noise may disappear while driving and appear only when the clutch pedal is pressed. In this case, the box itself has nothing to do with it - the clutch is to blame. It is not the disc itself that is worn out, but the release bearing. Its resource is about 60 thousand kilometers. The element produces a characteristic hum and whistle, which intensifies over time.

Disassembling the gearbox

In some cases, this happens - the box breaks, but the apparent reason is not immediately established. To identify it, the gearbox should be dismantled. Not everyone can immediately get to the service station, and you have to do the removal of the box yourself. For safety, disassembling it must be done by two people, since some parts with significant mass can injure a person if they fall.

First, remove the “+” terminal from the battery and drain the liquid from the box. After this procedure, remove the tray protection. There is a wire on the crankcase, called ground, attached with a bolt. This wire should be removed and moved slightly to the side so that it does not break during subsequent disassembly of the VAZ 2108 gearbox. First, remove the clutch cable. Then we separate the block from the starter relay. Unscrew the 3 bolts and disconnect the starter. Then we go under the car. Loosen the clamp and unhook the joint from the gear selector rod. Unscrew the speedometer drive cable and the wiring for the reverse speed light.

Then you need to unscrew the nuts located on the suspension arm. Unscrew the entire nut that connects the bracket and the brace. Next, turn the guy wires to the sides so that they don’t interfere with continuing disassembly. The cotter pin of the nut itself, which is responsible for securing the ball joint to the steering handle, should be unscrewed and pulled out. The tie rod assembly nuts should also be unscrewed.

The next thing is to knock out the ball pin from the rotation handle post. Then unscrew the 2 bolts and disconnect the ball joint with the steering knuckle. The shank should be knocked out from one of the CV joints of the drive wheels. This is where you need a mount. One CV joint has been freed, the second one should also be freed.

Then remove the crankcase cover. The tightening located between it and the cylinder block, which is attached to 3 bolts, should be loosened. Therefore, after removing the VAZ 2108 5 speed gearbox. the motor will remain without a lower support, and then you need to secure it. You need to do it like this:

Take a powerful wooden beam, the length of which is approximately 1.5 m.
Secure the front strut supports so that it is positioned above the engine.
Secure the motor to the beam using a chain or strong ropes.

After the motor is secured, you can safely disconnect the rear and left support from the frame of the machine. Then, move the box in the opposite direction from the engine until the input shaft is freed from the clutch. Be careful not to break the petals located on the clutch diaphragm spring.

In principle, the entire procedure is completed, now the gearbox from the VAZ 2108 engine can be further disassembled to replace worn elements.

Improving the gearbox by selecting gear ratios

Many techniques used in transmission tuning have been tested in motor sports. For any car, especially a sports one, the gearbox is an important element in realizing the dynamic qualities of the engine. Correctly selected gear ratios of the VAZ 2108 gearbox will make a car with a rather weak power unit fast.

Cars that require serious preparation use cam gearboxes. They are determined by many advantages - they can withstand quite large loads (using the shape of the tooth and the way the gear-cam clutch engages). They need less time to switch gears (due to incompletely squeezing the clutch or not squeezing it at all), especially since they do not destroy synchronizers (which simply do not exist).

But still, cam gearboxes are practically unsuitable for regular highway driving, since they produce a lot of noise (thanks to the use of spur gear pairs), they have “hard gear shifting” and have a fairly short resource. In addition, they are much more expensive than synchronized ones and must be constantly professionally maintained.

Synchronized gearboxes differ from conventional gearboxes only in gear ratios. Certain situations (VAZ eighth model) allow expansion to sixth gear. Good operation of the gearbox is achieved by effective selection of gear ratios of the main gearbox pair, the input shaft and the driven gears of the secondary shaft. The choice of gear ratios depends on the power and instantaneous capabilities of the engine, wheel diameter, and most importantly, on the desires of the motorist.

The gear ratio of the VAZ 2108 gearbox means the ratio of the number of teeth on the driven gear to the number of teeth on the drive gear. If it is increased, the transmission will become “more powerful”, also “shorter”, in a different way, the engine will turn the required number of revolutions. The car picks up speed quickly too, you just need to change gears often. This moment will only be reflected in a certain reduction in the maximum speed of the applied transmission.

Using an example, let’s take driving a VAZ eighth model with a 1.3 liter engine. with the main pair 4.5. It feels as if something very powerful was placed in the engine compartment, definitely not from a VAZ. Although the driver often needs to shift the gearshift knob of the VAZ 2108, the car is the first during any action, even at a traffic light. In sports cars, the gears used are the most “extreme” ones - 4.7, and on motocross cars - just 5.1.

Types of malfunctions and their causes

In order to correctly determine the malfunction and its cause, it is necessary not only to know the principle of operation of the mechanism, but to notice all the symptoms of something wrong.
“Flying” gear – the gear block associated with this very gear has worn out. Aged locks on the clutch and gear also manifest themselves in a similar way.

Rapid wear of some elements occurs due to violations in the operation of the vehicle, which are clearly stated in the instructions of the car manufacturer. Changing gears at the wrong speed limit has a detrimental effect on many vehicle systems, including the gearbox. Experts recommend doing this around 3000-3500 rpm. Instant speed changes without observing the required time interval of 2 seconds, especially with a broken or incorrectly configured clutch, also cause very rapid wear of gearbox elements. This results in an excessive load on the synchronizers, which affects the gear block and leads to their failure.

During repairs, an incompetent specialist or a careless owner often makes the same mistake - the engagement clutch is not replaced.

It is quite easy to determine whether the clutch in the gearbox was replaced after repairs in the cabin or not. The element that has not been replaced begins to produce a fairly distinct “crunch” when shifting a gear that is not working before repair. If the state of the mechanism is very neglected, then a minimal overhaul will no longer save the situation.

Each gearbox has an acceptable noise limit. If the sounds produced by the mechanism exceed the usual limit, then something is wrong. Based on this, we can say with confidence that not a single gearbox in a car operates absolutely silently.

GOST level of external noise for a standard gearbox is a maximum of 96 dB, and internal noise is 78 dB.

Unstable engine speed can also cause noise in the transmission. Therefore, if you doubt the serviceability of the device, it is better to send the car for diagnostics.

Hard shifts, idle shifting, slipping gears - all this can be treated with a gearbox overhaul. The reason, like the malfunction itself, can be different, depending on many factors, because a car is a complex mechanism with a mass of interconnected components and systems.

How to replace a gearbox on a VAZ 2108 car

Repairing a VAZ 2108 gearbox is not reasonable in all cases; exchange in most situations is more reasonable and simpler. You can buy a gearbox new or used. The choice of unit is determined by the advantages and financial capabilities of the car enthusiast. It is profitable to buy a used box for disassembly. There are serviceable spare parts on sale with less than half capacity. The advantages of used units are obvious.

The disassembled gearbox is exactly free of manufacturing defects (it has been tested on the highway), it has been diagnosed by professionals from the service center before sale, it is serviceable and efficient, and for all that, its cost is less than that of a new one. In reality, for a VAZ 2108 gearbox, the cost is determined by the node type (4 or 5 range) and the level of wear. By installing this gearbox, you can save money and time on repairs.

You can replace the VAZ 2108 gearbox from a 4-speed to a 5-speed. Then the car’s capabilities will become several times greater, this will also depend on the type of engine. After all, it happens that with a 4-range gearbox, the car seems to lack one more speed.

If the gearbox secondary shaft breaks, it should be corrected

It is necessary to clamp the secondary shaft of the VAZ 2108 gearbox in a vice with metal soft pads on the lips.
Using 2 pry bars, you need to compress the ball bearing located behind the secondary shaft.
Remove the thrust ring.
Remove the 4th speed driven gear.
Then remove the needle bearing of the 4th speed driven gear and be sure to mark it.
Then remove the spacer washer from the secondary shaft.
Using 2 pry bars, move the 3rd and 4th speed synchronizers through the third speed gear from the splines of the secondary shaft.
Remove the 4th speed needle bearing bushing.
Then remove the 3rd and 4th speed synchronizer with the 4th speed locking washer. Mark the synchronizer locking washer in relation to the synchronizer clutch.
Then remove the blocker from the secondary shaft. the 3rd speed gear synchronizer washer, then mark it in relation to the synchronizer clutch.
Remove the 3rd speed gear from the output shaft.
Remove the 3rd speed gear needle bearing from the output shaft, then mark the needle bearing.
Remove the thrust washer of the thrust rings.
Remove the 2 thrust half-rings from the secondary shaft.
Remove the ball that secures it from the hole on the secondary shaft.
Remove the 2nd speed gear from the output shaft.
Remove the 2nd gear needle bearing, then mark it.
Remove the lock washer (spring) from the secondary shaft.
Place the secondary shaft of the 1st speed gear on the lips of the vice, then, hitting the end of the secondary shaft with a wooden mallet, press the 1st and 2nd speed synchronizer from the splines of the secondary shaft.
Remove the 1st and 2nd speed synchronizer from the secondary shaft from the lock. 2nd speed synchronizer washer.
Next, remove the ring that blocks 1st speed from the secondary shaft, then mark the synchronizer blocking washer in relation to the synchronizer clutch.
Remove the first speed gear.
Remove the locking ring.
Slightly release the lock of the 1st speed needle bearing and remove it by moving the latter along the length of the secondary shaft. Then mark the needle bearing.
Turn the secondary shaft over, using 2 large screwdrivers, press the inner bearing washer in front of the secondary shaft. Then remove the thrust washer.
Clean, rinse and dry the secondary shaft elements thoroughly. It's good to inspect them.
Check the condition of the shafts. If the bearings are worn, they need to be replaced. The shaft splines must be free of dents and all sorts of defects.
Check the position of the VAZ 2108 gearbox gear. In case of chipped teeth or any other damage, the gears need to be replaced.
Check the condition of the bearings and replace them if damaged.
The radial clearance of existing ball bearings should not exceed 0.05 millimeters. Check this method with an indicator.
Next, check the lock position. synchronizer rings. If there are nicks and all sorts of chips, they should be replaced.
Next, check the gap between the gears and the blocking rings. The smallest gap should be 0.6 millimeters. In case of smaller gap, block. the ring should be changed.
If there are burrs and dents on the thrust washers and retaining rings, be sure to replace them.
Assemble the secondary shaft in the same way as you removed it. Place the blocking rings with the marks marked earlier. Install new rings in such a way that they align with the grooves of the hub.
Press the ball bearing on the rear of the secondary shaft using the required mandrel, using extreme force, to the ring inside the bearing
After assembly, you should check the operation of the synchronizers. By moving their clutches manually to the proper speed engagement position.
In general, this is how the gearbox bearings of a VAZ car are removed.

Existing checkpoint rows

Gearbox rows VAZ 2108: 1 – 3.42, 2 – 2.11, 3 – 1.35, 4 – 0.96, 5 – 0.78, 6 – 0.69

They are also called “commercial” because for many years they were considered quite famous, as well as being sold in series. In general, this is true at the moment. The first speed is extended, the second and fourth are shortened. Any changes are minimal (five percent each), and this is enough to correct the shortcomings of the standard series. In most cases it is installed with GP 4.1. The good news is that it is within the normal range. Gives improved overclocking.

Gearbox for front-wheel drive VAZs

The first VAZs of the eighth model, which rolled off the assembly line back in 1984 of the last century. They were equipped with 2-shaft gearboxes, which were combined in 1 housing with a differential. Since those distant times, gearboxes have been updated in every possible way. But since some changes have occurred in the elements, they are not entirely interchangeable. The first VAZs of the eighth model were equipped with 4 VAZ 2108 gearboxes, as well as 5-range gearboxes without a dipstick.

At the moment there are practically none of these left. In 4-band, the main pairs were 4.1, also 3.9. In five-band 3.9, also 3.7. The concern decided not to indulge in a large selection and used only one main pair - 3.7. As for the gearbox ratios, they were, and still are, only one for all cars.

Gear selection mechanism:

1 – gear selection lever (forward);	6 – reverse fork axis;
2 – guide axis of locking brackets;	7 – locking bracket;
3 – axis of the gear selection lever;	8 – reverse fork;
4 – spring;	9 – gear selection lever (reverse);
5 – retaining ring;	10 – housing of the gear selection mechanism.

Two axles are mounted in the housing (10) of the gear selection mechanism. A three-year-old gear selector lever and two locking brackets (7 and 12) are installed on the axis (3). The other axis (2) passes through the holes of the locking brackets, securing them from turning. The gear selector lever arm (1) is used to engage P forward gear, the lever arm (9) is used to engage reverse gear, and the third arm is used by the gear selector rod lever. A fork (8) for engaging reverse gear is installed on the axle (6).

Oil is poured into the gearbox of a VAZ 2110, the level of which should be between the control marks of the oil level indicator.

Tips for replacing the gearbox

Many drivers are in favor of changing the 4-range gearbox on the VAZ 2108 to a 5-range gearbox. Thus, the speed probability of the car increases, the acceleration dynamics are improved. However, the 4-range gearbox is already a thing of the past. And to modernize your car, a 5-speed gearbox is just right, and in some cases they even install a 6-speed gearbox, for which the same VAZ 2108 gearbox bearings are suitable.

What to choose

The design of the VAZ 2109 gearbox is imperfect, but this is not a good reason to change it completely. The design itself is reliable, it just requires some modifications. The best option is to replace the problematic part, which causes frequent unit breakdowns, or install new components.

If you need to change the gear ratios of your original transmission, replacing a pair of gears from 17-tooth to 15-tooth parts will do. This modernization increases the efficiency of acceleration, the transition time from gear to gear is reduced, but the maximum speed of the car decreases. Perfect for traveling in urban areas.
Installing sports gears makes the gears “longer”, that is, switching from one gear to another is required less often, while the dynamics of acceleration and maximum speed are practically not lost. This gearbox tuning is suitable for those who want to increase the speed characteristics of their nine. Mainly used after replacing the engine with a more powerful analogue.
You can try replacing the original secondary shaft of the nine. The problem with this part is that it is hollow inside. Due to dynamic loads on the assembly, it often happened that this particular shaft shattered into pieces, which led to the final breakdown of the entire gearbox due to fragments stuck in the teeth. Replacement is made with a solid analog shaft for a pair of gears with a gear ratio of 4.13.
Want to make your car more agile on the track? Buy additional sports hub bearings for tuning. They will slightly improve the performance of the chassis, but the main thing is that they are more reliable than factory parts.
Start adjusting the differential, but do it only in reputable auto repair shops and service stations. Incorrect adjustment of the part will lead to frequent breakdowns or loss of vehicle controllability.

There are a lot of tips and fairly detailed instructions on how to independently replace a part of an assembly or the entire assembly, but you don’t need to do this if you don’t know the architecture of the car. When carrying out many works, practice and clear knowledge of the matter are required, so it is better to entrust the work to the masters at the service station.

If you need to improve the gear shift mechanism of a VAZ 2109, then before modifying it you need to purchase some additional parts and replace the factory ones with them. This option for solving problems is the cheapest and simplest. Installing an automatic transmission on a VAZ 2109 is not always justified. This modification will simplify driving the car, slightly increase the working life of the unit and allow it to smoothly transition from one speed mode to another. On the other hand, not every owner of a nine can handle repairs, maintenance and installation of automation, so taking into account the costs, this solution is not effective.