Limited slip differential (self-locking differential) for Lada 4x4 and Chevrolet Niva (rear gearbox), classic VAZ.

A self-locking differential (popularly “self-locking”) is a device that automatically redistributes power flows from the difference in torque on the drive wheels, depending on their coefficient of adhesion to the road. In other words, a wheel that is hanging out or slipping will receive a minimal amount of torque. Is such a differential needed for Lada 4×4?

Peculiarities

Just because a vehicle comes with all-wheel drive does not mean it has all-terrain capabilities. Often, due to their design features, SUVs fall into the treacherous traps of sandy and washed-out roads. Domestic cars are far from an exception. There is an assumption that the self-locking differential on the Niva will be an important addition, especially if the owner plans to actively use the car in off-road conditions.

The limited slip differential, or self-block, as the part in question is also called, provides wheel stop automatically at the required time interval. It can be described as an intermediate option between the free analogue and complete blocking. The capabilities of both devices are optimally combined in the self-block.

My review of Dak and Racing

It just so happened that I had to use the two mentioned types of self-blocks. Their price at the time of purchase was almost the same - ten thousand, the installation is also the same, but the result is completely different.

If the DAK failed after about six months, and not in intensive use, but when driving on ordinary forest roads, then the Togliatti one (val racing) is still working.

Maybe I was just unlucky, but I have repeatedly come across reports that there are problems with the quality of the metal in the production of DAKs. So think for yourself.

Is it necessary?

There are a huge number of opinions about whether a self-block is needed at all, and the most polar ones - from “why is it needed” to “is absolutely necessary.” As always, the choice is a personal matter and everyone must make it themselves.

Again, I will only express my opinion.

It seems to me that everything depends on how and where you move in your car. If you go to the country or mostly on asphalt, then you definitely don’t need a self-block.

Also interesting: New Chevrolet Niva presented

The situation is approximately the same if your hobby is off-roading and you are engaged in conquering impassable roads. Here, such “half measures” as self-locking will not work and here you need a full manual differential lock.

However, if your task is to overcome not too severe off-road conditions, driving along a wet, broken forest road, i.e. normal conditions without extreme conditions, then self-block can be a good helper in such conditions.

Maybe it seems to me, maybe I have the self-locking set up this way, maybe that’s not the issue, but often when the car starts to “slip”, a jerk in the opposite direction suddenly appears. It’s as if the car first went to where the wheel was blocked, and then it gained momentum again, and the car jerks in the opposite direction.

Maybe this is not related to the self-blocking system, but I know this feature of the car’s behavior on a broken road and am always ready for it. Perhaps this will be useful to someone. In all respects the behavior of the car is absolutely normal

A self-locking differential for the Niva is a good addition that, if used correctly, can significantly improve its off-road properties.

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Varieties

There are two main groups of self-locking differentials. The first type works depending on the angular speed parameters along the axes of the vehicle. In turn, these modifications are divided into several subtypes, namely:

• disk versions;
• models equipped with a viscous coupling;
• options with electronic action.

The second type includes mechanisms that are locked in accordance with the torsional moments on the axes. This group includes worm modifications.

In addition, there are inter-axle and inter-wheel self-blocks. With their help, torque is distributed between axles or wheels, respectively. The design of the mechanism, which can be symmetrical or asymmetrical, directly depends on the moment of force dispersion. On all-wheel drive SUVs, three sets of differentials are installed simultaneously, two between the wheels, one between the axles.

Nivov transmission units

The legendary Niva is an all-wheel drive vehicle. This ensures unprecedented road holding and reliability comparable to expensive high-performance cars. With the exception of updated versions under the Chevrolet brand, the traditional Niva has always had a rather modest design, but this did not prevent it from being the undisputed leader among car owners who prefer high-end car platforms.

What distinguishes the Niva's chassis from other all-wheel drive vehicles is the transmission of torque to two axles at once without disabling the axles, which significantly affects cross-country ability while simultaneously reducing the influence of critical loads on the transmission. This same quality makes this legendary Russian SUV very uneconomical in terms of fuel consumption.

The developed Niva transmission turned out to be so successful and efficient that it later became a prototype for the Vitara. This made the new model more adaptable to difficult roads. Niva transmission units can easily meet the requirements of any engine up to 2 liters, so if you want to upgrade, think about the fact that each car has its own capabilities. Many advantages are due precisely to the circuit and design of the transmission.

Niva transmission and its components:

• front-wheel drive;
• front axle;
• wheel grip;
• manual transmission;
• driveshaft (front);
• shaft (intermediate);
• transfer case;
• shift lever;
• center differential and locking lever;
• wheel differentials;
• driveshaft (rear);
• rear axle;
• rear drive.

The design implies the following states:

• unlocked differential;
• locked differential;
• low gear when engaged;
• neutral position;
• top gear engaged.

The features of the Nivov transmission include the presence of a center differential that connects the rear and front axles. As a result, the wheels can rotate not only at different angles, but also at different angular speeds, which significantly affects controllability in impassable roads.

The key difference between the Niva’s center differential is the ability to lock when driveshafts rotate with the same characteristics. The center differential is manually locked only in difficult terrain conditions, when you need to overcome a large hole, rut or snow drift without slipping.

In practice, mechanical locking, although somewhat inconvenient, turns out to be better than the modern electromagnetic clutch used for these purposes. For example, the Renault Duster is not so easy to cope with the task in harsh off-road conditions, since the digital control unit can provide limited torque transmission. However, this effect will not be observed in a Niva with a mechanical lock.

Leaving the center differential locked will not only cause increased wear, but will also significantly reduce the vehicle's handling. The activated differential lock mode will be indicated by a lit indicator on the Niva dashboard. Please note that locking will not prevent one wheel from losing traction.

To overcome difficult areas, the transmission allows the use of a low gear with a high gear ratio (2.135); in the highest gear, the parameter is 1.2 and is intended for driving in normal conditions. The transfer case indicates different high and low gear modes. The lower one is turned on before entering a snowy area, unsteady soils, hills, and when a towed load is connected.

Some drivers master the skill of shifting gears at speeds of 30-35 km/h. Otherwise, you will have to stop the car and perform the operation in the parking lot.

Please note that Niva requires a competent approach to the selection of tires, the quality of which can affect the degree of wear of the transmission in just one season. The tires must be the same in terms of wear and, of course, in size. Different characteristics will lead to increased load on the transmission and slipping in low gear, and during normal driving will increase wear on the differentials.

1, 3 – Front wheel drive; 2 – front axle; 4 – clutch; 5 – gearbox; 6 – front driveshaft; 7 – intermediate shaft; 8 – transfer case; 9 – transfer case gear shift lever; 10 – differential lock lever;

11 – rear propeller shaft; 12 – rear axle; I – differential unlocked; II – differential locked; III – low gear engaged; IV – neutral position; V – high gear engaged

Transmission Specifications

The Niva car is all-wheel drive, i.e. All wheels are driven. All-wheel drive is permanent: torque from the engine is always transmitted to both axles at once (the axles are not disabled). This scheme increases the vehicle’s cross-country ability, while simultaneously reducing the load on the transmission units, but slightly increases fuel consumption.

The front and rear axles are connected through a center differential, allowing the front and rear wheels to rotate at different angular speeds depending on the trajectory and driving conditions. The center differential is located in the transfer case and is similar to the cross-axle differentials located in the front and rear axles.

However, unlike them, the center differential can be forcibly locked (the locking lever is located on the floor tunnel). In this case, the front and rear driveshafts become rigidly connected to each other and rotate at the same frequency. This significantly increases the vehicle’s maneuverability (on slippery slopes, in mud, snow, etc.

), but worsens handling and increases wear on transmission parts and tires on surfaces with good grip. Therefore, the differential lock can only be used to overcome difficult areas and at low speeds. A warning lamp on the instrument panel serves to warn the driver that the locking mode is on.

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You can engage the differential lock while the car is moving, if the wheels do not slip. Locking the center differential does not relieve the car from the danger of “diagonal hanging”, when one of the wheels on each axle loses traction with the ground - in this case, pour soil under the suspended wheels or dig it under the others.

To increase the torque supplied to the wheels, a low gear in the transfer case is used, its gear ratio is 2.135. The highest gear, intended for normal driving conditions, has a gear ratio of 1.20. Thus, the driver can use one of two rows of gear ratios - with a high or low gear in the transfer case.

The total gear ratios of the “top” row (from 1st to 5th gear) are 4.40; 2.52; 1.63; 1.20; 0.98, “lower” – 7.82; 4.47; 2.90; 2.13; 1.75. The low gear in the transfer case is switched on before overcoming snowy, sandy areas, steep climbs, when towing loads, etc., when there is a lack of engine traction or for driving at very low speeds.

It is necessary to engage a low gear in the transfer case in advance, with the car stationary, since the gear shift clutch does not have synchronizers. With some skill, it is possible to engage the highest gear even when driving at a speed no higher than 30–35 km/h, however, if possible, it is better to reduce the speed or stop.

A vehicle with permanent all-wheel drive places special demands on tires. They should be the same not only in size, but also in the degree of wear. Different tire rolling radii will cause increased wear on the differentials under normal driving conditions, and when the lock is engaged, increased wear on other transmission parts and wheel slip.

Video

The normal position for the RK handles, ensuring adequate behavior on the road of good quality:

Front - away from you Back - towards you

The special operating mode of the transmission is switched on not long before the car begins to overcome an obstacle (rut, mud, ford or rise). The transition to the lowest row must be done while stopping. Returning to top gear is allowed on the go, although it causes problems for beginners due to the lack of the usual synchronizer.

It is somewhat more difficult to properly handle the forced manual locking of the center differential. On the contrary, it turns on when the car moves slightly (up to 20 km/h) due to misalignment of the grooves on the locking clutch, satellites and ring gear. To simplify turning the lever into the desired position, taking into account the Niva 2121 transfer case, pick up a small speed, then, shaking the steering wheel, pull the handle towards you.

Problems can also arise when disengaging the lockout, as the clutch teeth literally catch on the ring gear. Engage reverse and, rocking the steering wheel, push the lever away from you. This action is performed immediately after overcoming a difficult section in order to avoid overloading the gearbox. It is most effective to disable the differential together with the transition to lower stages.

Which is better to install a self-locking differential on the Niva?

A domestic SUV can be equipped with an electronic, combined, mechanical or pneumatic self-block. The first type model has a significant advantage over other versions. To activate it, you just need to press a button. The mechanism operates automatically, but only if the car is moving at a speed that is less than the threshold. The system shuts down when it reaches a mode higher than the nominal parameter.

The pneumatic version is a device mounted on both axles. The advantages of the mechanism include its compact size; the operating principle is based on the use of a pneumatic system. Self-block mechanical type is the cheapest and simplest in design. Reliability and operational efficiency depend on two semi-axial and a pair of spacer couplings, as well as pins and springs.

Modified versions

The Niva's standard transmission, for all its advantages, often causes uncomfortable noise in the cabin. This is generally related to the design, but using engineering developments, you can modernize it and make the car much quieter.

This approach has already been applied in VAZ-21213 cars; as a result, even at a speed of 100 km/h you don’t feel any unpleasant noise, you can talk calmly and hear your interlocutor without effort. For these purposes, a number of modernization methods have been used: from unloading the floor near the transfer case and manual transmission mounts, reducing the load on shaft bearings to smoothing out peak torques under conditions of increasing loads on the transmission.

Also interesting: Niva Chevrolet gearbox repair

The noise in the modernized Niva transmission is comparable to that of a Zhiguli. It becomes more comfortable to be in the car when driving off-road. Upgrade costs are negligible; modification requires only the master's understanding of the design itself and a little time.

Parameters and selection criteria

The definition of a self-locking differential on a Niva is influenced by the car model, operating conditions, driving style, and other objective and subjective factors. For example, the ball version increases the load on the steering column, which radically changes the way the driver drives. This is fully expressed during turns and turns; if handled improperly, it leads to deformation of transmission parts.

The correct approach to choosing self-blocks is to take into account which axle of the vehicle will be equipped with the specified mechanism. This is due to the fact that the number of splines differs for different modifications. There can be 22 or 24 of them. Pay attention to the markings on the packaging. Usually there is information there, is it possible to install devices for a certain brand of car? Another point is the degree of transformation of the torsional moment (0.5 or 0.7). Here the choice depends on the owner of the car.

Turning the electric lock on and off.

Manual activation of the lock is possible by pressing and holding the button until the lock indicator turns on. Manual shutdown is done in the same way - by pressing a button.

Attention! Engage with the vehicle stationary or at speeds up to three miles per hour with minimal slippage. Switching on at a higher speed may damage the locking mechanism, resulting in denial of warranty repairs. We will deny warranty if the locking coupling or pins are damaged. After passing a difficult section, the blocking must be turned off.

It is not recommended to disable the locking under load, for example when turning. When the lock is loaded, it may not turn off immediately; as a result, the differential will be locked when it is not needed. In cold weather, the viscosity of the oil increases, which entails spontaneous activation of the lock. We recommend using synthetic oil in the cold season.

On the Chevrolet Niva it is possible to turn on all three differentials at the same time

. Thanks to this, the vehicle’s cross-country ability increases several times when driving off-road.

As already mentioned, the differential assembly consists of shafts and gears. With their help, the traction force is automatically distributed between the drive wheels. The differential is locked using a blocker (clutch)

. In this case, when the driver turns on the forced locking, the wheels “become” connected to each other. This helps ensure that they rotate evenly.

Differential assembly

If the center lock is forcibly engaged, then the front ones are also rigidly connected at once, which guarantees an even distribution of traction to all four wheels. Thus, the vehicle’s cross-country ability will be increased several times.

, which makes the Chevrolet Niva a real SUV.

Not all cars are equipped with blockers, and therefore they will be vulnerable off-road. In this regard, Chevrolet is a unique car that can move with both one-wheel drive and all-wheel drive.

, which allows him to feel confident even on mountain roads.

To engage the differential lock, pull the lever all the way to the left.

Forced blocking should be enabled in the following cases:

1. When overcoming difficult sections of the route. In this case, the blocking should be turned on in advance, even before leaving for such an area.
2. On steep climbs or slopes when wheel slip is possible.
3. When driving on sand.
4. When driving on snow or ice.

When the Niva moves on a regular road with a smooth surface, it will not need to lock all wheels. They will adhere normally to the surface and not slip, since the traction force from the engine will be distributed evenly over them. For this reason, when the car is moving on a good road where the wheels will not slip, the use of a differential will not be required.

Also interesting: Where is the fuel pump fuse for Niva Chevrolet

Advantages and disadvantages

To find out which is the best self-locking differential for the Niva, you need to compare the advantages and disadvantages in relation to the standard analogue of the car. The benefits include:

1. Increasing the vehicle's maneuverability on steep, sliding and bumpy surfaces.
2. There is no need to make changes to the design of the machine, since the self-block is mounted in place of the standard element. It is recommended to carry out installation work in a specialized workshop or do it yourself.
3. The mechanism in question operates automatically and does not require special training for the driver.

Disadvantages of installing a self-locking differential on a Niva:

• steering becomes tighter, which requires additional effort;
• the working life is less than that of the factory element;
• driving style changes when cornering;
• there is no complete guarantee of blocking.

Various modifications of self-blocks have their own nuances, depending on the manufacturer, type of development, and installed components.

Removing axle shafts and bearings

To install a self-locking differential on a Niva 4x4, you need to carefully and efficiently remove the axle shafts. A special puller will be required. Otherwise, this is problematic, since the metal sticks to the slots. Stages of dismantling axle shafts and bearings:

1. Unscrew all the bolt nuts on the plate element for fixing the axle bearing.
2. The brake block is secured with bolts or fittings of a suitable diameter. If you ignore this procedure, the brake lines will come off.
3. The axle shaft is removed directly using a special device.
4. To dismantle the bearings, you will need a hydraulic press, which will make it easier to fit the race onto the shaft with high precision.
5. Unscrew the wheel bearing nut and remove the bushing.
6. Unscrew the fastening nut securing the lever with the rotary cam.
7. Remove the stupor plate and remove the lever.
8. Disconnect all fasteners, disconnect the hub with the brake disc and the knuckle. Dismantle the bearing, having previously fixed the rotating element in a vice. The bearing is also installed by pressing.

Assembly of the unit

When you have decided on the best self-locking differential for the Niva, you can begin assembling the unit. Initially, they adjust the gaps, which is not so simple. For this purpose, special washers of different thicknesses are used. Alternatively, accuracy is determined using a steelyard. One edge of the cord (about a meter in length) is wound around the flange, and the second is fixed to the scales. Pull the device in the winding, not forgetting to mark the turning point.

To ensure correct functioning of the gearbox, the elements are sealed before assembling the parts. If this is not done, soon after installation defects may appear, even to the point of complete breakdown of some parts. After treating the surfaces with sealant, wait until it dries completely. Next, the gearbox is filled with new oil. All sealing components with deformations and a hint of leakage are replaced. The mechanisms are assembled in a mirror order. After the replacement and installation of parts is completed, you should check the operation of the brake unit. This is very important, since malfunction of parts affects road safety.

What are users saying?

As reviews indicate, it is not advisable to install a self-locking differential on a Niva in all cases. If the driver intends to constantly operate the vehicle on serious and difficult off-road conditions, installing a self-block makes sense. When driving regularly around the city or on a country road, this idea is irrelevant. The existing factory analogue copes well in such cases on its own, and it has a longer service life.

In addition, users recommend installing the mechanism themselves only if the owner has the appropriate skills and a clear understanding of the design features of the vehicle. Otherwise, use the services of a car service. The choice of the configuration of the self-block and the location of its installation depends solely on the preferences of the owner of the machine.