How to enable locking on a Chevrolet Niva

The Niva Chevrolet car belongs to the SUV family. Therefore, for better movement of this vehicle, the manufacturer equips differentials on its wheels. What is this device? What are its functions? How is the differential locked on a Chevrolet Niva? Qualified specialists provide answers to all questions posed in this article.

Functions of the differential device of the Niva Chevrolet

By automobile differential, experts mean a mechanical installation that includes a set of planetary gears and shafts. The functions of the Chevrolet Niva differential include the distribution of torque from the internal combustion engine of the vehicle to the drive wheels mounted on the same axle. Thanks to this, the car's wheels spin at different speeds.

The ability of the Chevrolet Niva wheels to spin at different speeds is very important when making turning movements. Especially when one wheel runs along a small radius, and the second wheel, located on the same axis, runs along a large radius. If there were no such device as an inter-wheel differential device, the vehicle's wheels would slip.

As a result of such spinning, the car would skid to the side, and the tires would wear out faster and lose their functional features.

When a Chevrolet Niva moves along a straight road at a constant speed, the inter-wheel differential device distributes the thrust from the internal combustion engine evenly between all wheels. This means that both driving wheels will rotate at the same speed. If any drive wheel slips, the differential will increase the traction force on the slipping wheel. As a standard, a passenger car is equipped with one cross-axle differential on the drive axle. There are three such devices for the Chevrolet Niva; they are installed on:

front axle;
rear axle;
at the center of the interaxial action.

A central differential device is needed to distribute the torque to both axles of the vehicle from the internal combustion engine.

VAZ 21213 transfer case and its structure, diagram, alignment, removal

Niva is a car that has been produced since 1977.
It differs from other domestic cars in that it has permanent all-wheel drive. Few car enthusiasts know what this means, although they have heard a lot about this feature of the vehicle; a diagram of the device can easily be found on the Internet. All-wheel drive in the Niva is equipped for all 4 wheels, and the center differential is locked. When the engine starts to rotate, an impulse is sent to the gearbox and transfer case, after which the torque is distributed to the front and rear axles simultaneously. Afterwards, the gearboxes are activated, and behind them the front and rear wheels of the Niva begin to rotate. Torque causes 4 wheels to rotate at once, which is why it is called full torque. But the rear wheels still drive.

https://www.youtube.com/watch?v=dOv4uxNwBXw

The Niva and its various modifications allow you to operate 3 differentials at once. Thanks to this factor, the vehicle’s cross-country ability increases significantly when driving in rural areas. The forced locking format involves connecting the driving wheels together, causing them to spin at different speeds. This approach allows you to use the maximum possible traction characteristics of the engine, which are transmitted to the wheels.

To lock the differential on the Niva, the manufacturer has provided a clutch for the locker. When forced locking is turned on, the wheels become interconnected and rotate in the same mode. When the inter-axle lock is activated, the axles located at the front and rear interact and distribute traction to all wheels. This mechanism is easy to use, which is confirmed by the unique cross-country ability of the Chevrolet Niva.

The VAZ 2121, in other words, “Niva”, entered mass production in the 70s of the last century. This car belongs to the class of off-road passenger cars. In the history of the domestic automobile industry, Niva became the first car whose design used all-wheel drive. Let's take a closer look at the transmission device.

The transmission in the Niva family (2121, 2131) is designed in such a way that all-wheel drive is supplied to 4 wheels. Also characteristic is the presence of a center differential. The transmission includes a gearbox, a transfer mechanism, a pair of cardan shafts, and both axles. A characteristic feature of the 2131 model is its elongated body.

Then it goes through the cardan shafts to the gearboxes. The front gearbox transmits torque to the wheels through the differential and constant velocity joints. Likewise for the rear, also protruding, driving wheels. It is precisely because the torque is distributed to 4 wheels simultaneously that the drive is called full drive. The designation is as follows – 4WD. Another domestic car, designed on a similar principle to the Niva, is the UAZ.

This mechanism is a kind of distributor of traction forces coming from the motor to the wheels. An important feature is that the latter have the ability to rotate at different speeds. The importance of having a differential mechanism is due to the fact that during turning maneuvers, the wheel located inside makes fewer revolutions when compared with the number of turns of the outer wheel.

In the absence of a differential mechanism, this would cause detrimental consequences, such as wear and damage, because the result would be the following: when turning, one wheel would be in a slip state, and the second would simply rub against the road surface. The design features of the Niva transmission provide for the presence of 3 differentials. They are located in each of the bridges and in the transfer mechanism.

When the car moves on a flat road and in a straight line with differentials, the traction force is divided equally between all 4 wheels. If there is insufficient adhesion of the wheels to the surface or slipping occurs, the differentials will redistribute the load on the slipping and sliding wheel so that the first receives more force, and the second, accordingly, less.

We have already mentioned UAZ. Despite many similarities, it should be understood that the VAZ’s all-wheel drive is made in the “pat-time” style. This means that when connected, the axes are firmly connected to each other, and rotation occurs at the same speeds. This device imposes some restrictions on the use of all-wheel drive - it can only be used in cases where road conditions allow slipping. In cases with hard asphalt roads and highways, it is recommended to switch the car to single-drive mode.

Sometimes you can come across a misconception about why a small handle is needed next to the shift lever on a Niva. Some car owners believe that it is needed to connect front-wheel drive. However, the front-wheel drive of this car is permanently connected. As is the rear one. Cars of the Niva family have permanent all-wheel drive. The handle actually serves to switch the operating modes of the differential of the transfer mechanism.

In the “forward” position, the differential operates as usual, but if you move it back, the differential is locked, and the forces from the motor are applied to the differentials of the axles, which makes the drive more rigid. It is worth noting that there are also special types of locks for front and rear axles.

In theory, when used in conditions where the car is stuck, it will be able to overcome the obstacle if there is sufficient traction on at least one wheel. In this case, it is better to lock the differential before overcoming an obstacle, but never after entering an area that is difficult to overcome. This application of locking will avoid wear and damage to the transmission.

Also interesting: Chevrolet Niva fuse box with description (up to 2009 model year)

Differential blocking of Niva Chevrolet

Since the Chevrolet Niva is an SUV, it needs the ability to enable blocking of all cross-wheel differential devices. This is caused by the need to increase the vehicle's cross-country ability in off-road conditions.

Let's consider the mechanism for blocking the differential device on the Chevrolet Niva:

if one of the wheels slips, the cross-axle differential will transfer traction force to it from the internal combustion engine;
the remaining wheels are at rest at this moment, because the traction force will not act on them;
the vehicle will stop.

Forced blocking of the cross-axle differential is necessary in order to make maximum use of the traction transmitted from the car engine to the drive wheels. Thanks to the action of the components of the differential (these are gears, shafts and a locking clutch), a rigid connection will occur between the drive wheels. That is why the torque will be evenly distributed between both vehicle axles - front and rear. Thus, the cross-country ability of the Chevrolet Niva SUV will increase.

Niva transfer case. Ways to eliminate vibration

The relatively complex scheme for distributing torque from the internal combustion engine to the wheels is explained by the universal purpose of the Niva 2121 - if used correctly, it can be used comfortably in the city and along muddy country roads. Such properties are ensured by the presence of a transfer case with a center differential lock, complementing a 4- or 5-speed manual transmission, depending on the year of manufacture.

The transfer case mechanism includes more than 60 independent parts, which is confirmed by the presented drawing. Therefore, it is quite prudent to name the main elements and their purpose.

Frame
Differential housing
Shafts
Couplings
Oil seals
Satellites
Gears
Flanges
Levers

Also interesting: Gearbox design Niva 2121, Niva 2131

A pair of gears are tightly seated on the drive shaft, one of them (large) is intended for high gear, the second (small) is responsible for low gear. They have serrations with straight and oblique profiles. The first ones are in contact with the coupling, the second ones - with the intermediate shaft. The inclusion of one or another row causes the coupling to move along the hub in the horizontal direction, after which it is connected to the gear on the transfer case drive shaft.

The intermediate position turns off the gearbox (the gearbox is open), and the vehicle cannot be moved in this mode. The front helical gear on the intermediate shaft is used to control the differential. The locking is engaged, or the rigid coupling of the drive shafts of both axles, is carried out through a clutch. The design is typical for modifications 21213 and 21214, and the latter is additionally equipped with a speed sensor drive.

In the operating state (with the transfer case reduction gear connected), the gear ratio in the first stage changes from 4.4 to 7.83, the second - from 2.52 to 4.58, the third - from 1.63 to 2.9, in the fourth - from 1.2 to 2.14, fifth - from 0.98 to 1.75, which is expressed in an increase in traction on the wheels.

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

Front - from yourself
Rear - 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.

The Niva 2121 transfer case is used to change the amount of torque and distribute it between the front and rear axles. The box has two gears with ratios of 1.200 and 2.135. The front and rear axles are constantly driven and connected by a center differential, which redistributes torque between them depending on the resistance to wheel movement.

The Niva 2131 transfer case is attached to the body floor on two rubber-metal brackets. To adjust its position relative to the intermediate shaft flange, the holes in the brackets are made oval, and adjusting shims can be installed between them and the body. The procedure for centering the box is described in the section Determining the causes of vibration and centering the transfer case.

The housing parts of the transfer case are cast from aluminum alloy and are connected to each other with studs and nuts. There is a hatch in the upper part of the crankcase, closed with a stamped steel cover. The front cover is centered on the crankcase using two locating pins. There are cardboard gaskets between the covers and the crankcase (during repairs, you can use a sealant gasket instead).

The drive shaft is mounted on two ball bearings in the sockets of the front cover and crankcase. The front bearing inner race is sandwiched between the shaft shoulder and the thrust ring by a self-locking shaft flange nut. The rear bearing inner race is sandwiched between the shaft shoulder and the thrust washer by a nut at the rear end of the shaft.

There are two drive gears on the drive shaft. The front (large) is the highest gear; it rotates freely on a heat-treated shaft journal. The rear (smaller) gear - the lowest gear - rotates freely on a heat-treated bushing mounted on the shaft with tension. The gears have two crowns. The helical (large) rings are in constant mesh with the corresponding gears of the intermediate shaft, and the gear shift clutch is connected to the spur (small) gears when the gear is engaged.

The Niva 2131 intermediate shaft is a block of two helical gears that are in constant mesh with the drive shaft gears. The front gear is also in mesh with the driven gear mounted on the differential housing.

The intermediate shaft rotates in two bearings: the front one is roller, the rear one is ball bearings. The shaft is secured against axial displacement by an adjusting ring in the groove of the outer ring of the rear bearing, which is sandwiched between the crankcase and the rear cover (the same as that of the drive shaft). A steel drive gear for the speedometer drive is pressed into the front end of the shaft.

On a VAZ-21214 car with distributed fuel injection, in addition to the mechanical speedometer drive, a speed sensor is installed on the transfer case.

The front end of the drive shaft of the Niva 2121 front axle rests on a ball bearing in the front axle drive housing, mounted on the front cover of the transfer case. The inner ring of the bearing is sandwiched between the shaft shoulder and the thrust ring by a self-locking shaft flange nut. The bearing is secured against axial displacement by a retaining ring that fits into a groove in the front axle drive housing.

The differential housing is detachable, both parts are connected by six bolts. The same bolts also secure the driven gear to the differential housing. The latter is mounted on two ball bearings. The inner race of the front bearing is held from displacement by a spacer spring washer resting on a retaining ring in a groove in the differential housing.

Also interesting: Niva Chevrolet transfer case device

The groove on the outer bearing race includes a mounting ring, sandwiched between the transfer case front cover and the front axle drive housing. Thus, the differential housing is held against axial displacement by the front bearing; the rear bearing is not fixed. The front of the differential housing has splines along which the locking clutch moves. When the lock is engaged, the clutch is connected to the gear on the front axle drive shaft, connecting it to the differential housing.

In the holes of the differential housing of the VAZ 2121 there is an axis of the satellites, held by two retaining rings. Under one of the rings there is a spring washer that prevents axial movement of the satellite axis. The satellites (bevel gears) located on the axle are in constant mesh with the axle drive gears.

The transfer case control is manual, with a mechanical lever drive. The driver uses the rear lever to change gears, and the front lever to engage the differential lock. The design of the gearbox control drives is similar. The lever swings in the longitudinal direction on an axis installed in the bracket eyes in front of the Niva 2131 transfer case.

To reduce friction, plastic bushings are inserted into the hole in the lever. The lower end of the lever fits into the groove of the rod and is fixed with a figured spring. The other end of the rod is connected to the fork of the corresponding clutch (gear shift or differential lock) and is secured with a bolt. The rod at the exit from the box is sealed with an oil seal and protected from dust by a rubber corrugated cover.

To fix the drive in the selected position, a ball lock is used - a spring-loaded ball fits into the grooves on the rods. There are three of them on the gear shift rod - for “neutral”, high and low gears; on the differential lock rod of the VAZ 2131 there are two (“on” and “off”). A switch is screwed into the front axle drive cover, which closes the warning lamp circuit when the differential lock is engaged.

the first - with a gear ratio of 1.2;
the second, lowered – with the number 2.135;
neutral

21213 (modifications 21213-1800020-01 and 21213-1800020-02):
21214 (modifications 21214-1800020-01, 21214-1800020-02, 21214-1800020-10).

different control mechanism (with one lever);
an additional support was installed (on a simple Niva the RK is mounted on two supports, on a VAZ 2123 car - on three supports).

vibration in the body at various speeds when the car is moving;
vibration when the vehicle starts moving;
noise in the transfer case when the car is slipping or turning;
difficult upshift or downshift, difficult engagement of the lock.

driveshafts are poorly secured;
wheels are not balanced;
there is play in the cardan crosspieces (vibration is especially affected by play in the rear driveshaft crosspieces);
The vibration comes from the engine itself.

hang the car on a lift;
loosen the transfer case;
start the engine;
engage the gear and accelerate the car according to the speedometer to the speed at which vibration occurs (often it occurs at speeds from 40 to 80 km/h);
without using the brakes, reduce the engine speed, then turn off the ignition.

dismantle the front passenger seat in the cabin;
remove the floor tunnel lining;
in the cabin we move aside the carpet covering the body amplifier (in front of the handbrake lever);
remove the transfer case (alternatively, you can simply hang it up, but removing the third support makes it easier to install);
We attach the bracket of the new support to the body of the RC;
we install the transfer case in place, center it in the optimal position, and fasten the side supports;
we combine the third support with the body, drill two holes in the bottom;
Using washers, bolts and nuts (from the kit) we attach the support to the bottom of the body.

in the cabin we dismantle the plastic lining of the gearbox and gearbox levers;
unscrew the knobs of the transfer case shift levers, remove the casing under them;
disconnect the speedometer cable, for RK 21214 you will need to additionally disconnect the speed sensor;
we unscrew the bolts with nuts securing the elastic coupling of the front and rear propeller shafts; in order to remove the bolts, the cardan shafts must be turned - they are removed one at a time in one specific position of the shaft;
We install a jack (or other support) under the transfer case and mark the places where the side supports of the RC were attached. This is done in order to minimize the alignment of the transfer case during installation;
unscrew the 4 nuts securing the gearbox to the gearbox;
unscrew the 4 fastenings of the RC supports to the car body;
Now all that remains is to dismantle the transfer case.

How to properly use the cross-axle differential locking functions on a Chevrolet Niva

When using a differential lock on a Chevrolet Niva, experts recommend adhering to several rules.

Rule No. 1 - the specifics of switching the transfer case to lower gears. This switching must be done when the vehicle is stopped.

Rule No. 2 - enable the differential locking process. This is only possible when the car is driving non-stop.

Rule #3 – Downshift. This action is allowed to be performed without stopping the Chevrolet Niva.

Rule No. 4 – ensuring optimal operation of the cross-axle differential. To do this, the driver will need to periodically switch the differential device lever on the transfer case. Frequency – once a week (especially in the winter season).

How to determine whether the differential lock is engaged on a Chevrolet Niva

You can determine whether the inter-wheel differential device is locked without even leaving the Chevrolet Niva interior. Let's look at how to do this:

Find two control levers between the passenger and driver's seats:
machine transfer case control lever (with short handle);
move the transfer case control lever forward - this will engage a lower gear to the drive axles of the wheels from the gearbox.
Move the transfer case control lever back - this will disengage the downshift.
Move the transfer case control lever left and right. This will switch the blocking of cross-wheel differential devices:
to the right - shutdown.

As you can see, with the transfer case control lever you can not only change gear levels, but also control the process of blocking the cross-wheel differential device. This is due to the fact that the car differential lock is part of the functioning of the all-wheel drive mechanism of the Chevrolet Niva. The locking switched on at the right moment facilitates the unhindered movement of the SUV in difficult road conditions.