VAZ 2108 - Gearbox: mechanism device and its repair

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

The article describes how to repair a gearbox in a VAZ 2108 car. All points, details and nuances.

VAZ 2108 - Gearbox: arrangement of components, its repair and improvement

Domestic car is a front-wheel drive car, and the engine is placed transversely, used to move along the tracks. The metal body is made according to the hatchback type, which has 3 doors. The back door is designed for loading and unloading luggage. When transporting long and oversized luggage, the back row folds - this moment increases the luggage compartment.

4-cylinder carbureted 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 handling of the car when cornering, even during wet roads. During long-term use of the car, wear of many elements occurs, the fasteners of the assemblies are loosened and the adjustable values are violated.

Checkpoint is the most reliable element in the car. The breakdown of this mechanism happens quite rarely, compared with other parts. And for all that, a complete or partial failure of it makes it completely unsuitable for furthercar application. It will simply be impossible to operate the car for its intended purpose. In addition, a tow truck will be required to deliver the car for gearbox repair.

Predominant types of breakdowns

One of the types of gearbox breakdowns on the VAZ 2108 is bearing wear or lack of oil in the gear shift unit. And for all that, this damage is very easy to fix by changing the oil or changing the bearings. It is quite another if we are talking about more serious breakdowns associated with axial rearrangement of the shafts, distortion of the gearshift knob, jamming, unreasonable engagement, disengagement of gears, wear of fasteners, various nuts, and springs by deteriorating the flexibility of the balls - in such situations, without a full repair get by.

Design design and further repair of the gearbox

Repair of a VAZ 2108 gearbox is a very complex and time-consuming process, moreover, 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, little experience, as well as a lack of spare parts in stock. Gearbox - is considered a complex element of the car. It is able to change the traction force of the driving wheels of the car due to the meshing of gears with different numbers of teeth.

In addition, it provides reverse and long-term separation of the motor (together with the clutch) with other transmission elements, while the car is standing or moving by inertia. Gear engagement with differentthe number of teeth is realized by their movement. The drive shaft is connected to the driven clutch disc, while the driven shaft is connected to other transmission elements.

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

Gearbox disassembly

In some cases, it happens - the box breaks, and the visible reason is not immediately established. To identify it, the checkpoint should be dismantled. Not everyone and not always can immediately get to the service station, and you have to do the removal of the box yourself. For safety, it must be disassembled by two people, since some parts with a 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 pan protection. There is a wire on the crankcase called "ground" attached with a bolt. This wire should be removed and moved a little to the side so that it does not break during subsequent disassembly at the VAZ 2108 checkpoint. First remove the clutch cable. After we separate the block from the starter relay. Unscrew 3 bolts and disconnect the starter. Then we go under the car. It is necessary to loosen the clamp and unhook the hinge from the gear selector rod. Unscrew the speedometer drive cable and the wires for turning on the reverse speed light.

After you need to unscrew the nuts located on the suspension arm. Unscrew the entire nut that connects the bracket and the brace. Next - rotatestretch marks to the sides so as not to interfere with the continuation of disassembly. The cotter pin of the nut itself, which is responsible for attaching the ball joint to the steering handle, should be unscrewed and pulled out. The nuts of the tie rod assembly should also be unscrewed.

The next thing is to knock out the ball pin from the turn handle bar. Then we unscrew 2 bolts and disconnect the ball joint with the knuckle. From the 1st of the CV joints of the drive wheels, the shank should be knocked out. Here you need a mount. One CV joint has been released, the second one should also be released.

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

• Take a powerful wooden beam, the length of which is approximately 1.5 m.
• Fix the front strut mounts so that it is placed above the motor.
• Fix the motor to the beam using a chain or the strongest ropes.

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

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

Improving the gearbox by selecting gear ratios

SetThe techniques used in transmission tuning have been tested in motor sports. For any car, especially a sports car, the gearbox is an important element in the implementation of 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.

Autos, which are serious training, 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 shift gears (due to incomplete clutch release or, in general, without squeezing), all the more they do not destroy synchronizers (which simply do not exist).

But still, cam gearboxes are practically unsuitable for normal track advancement, as they produce a lot of noise (due to the use of spur gear pairs), they have a "hard gear shift" and have a rather small resource. In addition, they are much more expensive than synchronized ones and must be maintained professionally at all times.

Synchronized gearboxes differ from conventional gearboxes only in gear ratios. Certain situations (VAZ of the eighth model) allow expansion to sixth gear. The good work of the gearbox is carried out by an effective selection of the gear ratios of the main pair of the gearbox, the input shaft and the driven gears of the secondary shaft. The choice of gear ratios is due to power, as well as instantaneousmotor capabilities, wheel diameter, and most importantly, from the desires of the motorist.

Under the gear ratio of the VAZ 2108 gearbox, they mean 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”, otherwise, the engine will wind up the required number of revolutions. The speed of the car is also quickly dialed, you only need to change gears often. This moment will only be reflected in a certain reduction in the highest transfer rate applied.

For example - we take a ride on the VAZ of the 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 VAZ. Although the driver often needs to switch the VAZ 2108 gearbox knob, but with any action, even at a traffic light, the car is the first. In sports cars, the most “extreme” gears are used - 4.7, and on cross-country cars - quite 5.1.

How to replace a gearbox on a VAZ 2108

Repair of the VAZ 2108 gearbox is not reasonable in all cases, the exchange in most situations is more reasonable and easier. You can buy a gearbox new or used. The choice of a node is determined by the advantages, financial capabilities of the motorist. It is profitable to buy a used box at parsing. In sales there are serviceable spare parts with less than half the capacity. The merits of used knots are clear.

Checkbox from parsing exactly without factory defects (tested by the track), passed diagnosticsservice center professionals before sale, it is serviceable and efficient, and for all its cost is less compared to a new one. In reality, for a VAZ 2108 gearbox, the cost is determined by the nodal type (4 or 5 range), wear level. By installing this checkpoint, you can save money and time for repairs.

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

If the gearbox output shaft is broken, it should be repaired

• You need to clamp the output shaft of the VAZ 2108 gearbox in a vise with soft metal lining on the lips.
• Using 2 pliers, you need to compress the ball bearing behind the output shaft.
• Remove thrust ring.
• Remove 4th speed driven gear.
• After remove the needle bearing of the 4th speed driven gear, and be sure to mark.
• Then remove the spacer from the secondary shaft.
• Using 2 pry bars through the 3rd speed gear, slide the 3rd and 4th speed synchronizer off the mainshaft splines.
• Remove the 4th speed needle bearing bush.
• Then remove the 3rd and 4th speed synchronizer with the 4th speed lock washer. Mark the synchronizer locking washer against the synchronizer clutch.
• After removing the lock from the secondary shaft. 3rd gear synchronizer washerspeed, after marking regarding the synchronizer clutch.
• Remove the 3rd speed gear from the secondary shaft.
• Remove the 3rd speed gear needle bearing from the output shaft, then mark the needle bearing.
• Remove thrust washer of thrust rings.
• Remove 2 thrust washers from output shaft.
• Remove the ball that fixes it from the hole on the secondary shaft.
• Remove the 2nd speed gear from the secondary 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 jaws of the vise, then hitting the end of the secondary shaft with a wooden mallet, press the synchronizer of the 1st and 2nd speeds from the splines of the secondary shaft.
• Remove the synchronizer of the 1st and 2nd speeds from the secondary shaft from the lock. 2nd speed synchronizer washer.
• Next, remove the ring that blocks the 1st speed from the secondary shaft, then mark the synchronizer blocking washer regarding the synchronizer clutch.
• Remove the first gear.
• Remove retaining ring.
• Slightly open the 1st speed needle bearing lock and remove it by sliding the latter along the length of the output shaft. After marking the needle bearing.
• Turn over the output shaft, using 2 large screwdrivers, press the inner bearing washer in front of the output shaft. Then remove the thrust washer.
• Clean well, rinse and dry the elements of the secondaryshaft. Good to see them.
• Check the condition of the shafts. If the bearings are worn, they must be replaced. 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, any other damage, the gears need to be changed.
• Check the condition of the bearings and replace them if damaged.
• The radial clearance of existing ball bearings must not exceed 0.05 millimeters. Check this method with an indicator.
• Next, check the position of the lock. synchronizer rings. If there are nicks and all sorts of chips, you should change them.
• Next, check the gap between the gears and the blocking rings. The smallest gap should be 0.6 millimeters. In the case of a smaller gap, blocking. the ring should be changed.
• If there are scuffs and dents on the thrust washers, as well as the retaining rings, be sure to change them.
• Assemble the secondary shaft in the same way as removed. Put the blocking rings with the marks marked earlier. Put the latest rings in such a way that they are aligned with the grooves of the hub.
• Press the ball bearing on the back of the secondary shaft with the help of the required mandrel, making extra effort, to the ring inside the bearing
• After you have collected, you should check the operation of the synchronizers. By moving their clutches by hand to engage the proper speeds.
• In general, the gearbox bearings of the VAZ car are removed in this way.

Existing checkpoint rows

Rows of the VAZ 2108 checkpoint: 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 marketable series. In general, this is true at the moment. Extended first speed, second and fourth - reduced. Any changes are minimalized (five percent each), and this is enough to correct the flaws in the regular range. 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 then, gearboxes have been updated in every possible way. But since there have been some changes in the elements, they are not entirely interchangeable. In the first VAZs of the eighth model, 4 VAZ 2108 gearboxes were installed, as well as 5-range gearboxes without a probe.

At the moment, there are practically none left. In the 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 choice and used only one main pair - 3.7. As for the gear ratios of the gearbox, as they were, and there are still only one for all cars.

Gearbox Replacement Tips

Many drivers are in favor of changing a 4-band gearbox to a 5-band gearbox for a VAZ 2108. Thus, the speed probabilities of the car increase, the acceleration dynamicsis being improved. However, a 4-speed gearbox is a thing of the past. And to upgrade your car, a 5-speed gearbox is just right, and in some cases they even put a 6-speed gearbox, for which the same VAZ 2108 gearbox bearings are suitable.

A few final words on all of the above

The VAZ gearbox of the eighth model implements the reforming of the torque transmitted from the motor in magnitude and direction. This moment is necessary to maintain the desired speed, and of the car's cross-country ability, to save the engine as much as possible and to advance the car in reverse. In addition, the gearbox separates the motor and transmission for stopping and parking the car, and also while coasting with the current motor. For all this, a gearbox is needed.