Niva 2121 transmission: diagram, description, video

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.

Diagram and description of the Niva 2121 transmission

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.

Tips for owners

To make driving your car comfortable, read some important points:

The usual, standard arrangement of the front and rear handles is forward and backward, respectively. Movement in this mode can and should be carried out in areas characterized by even and smooth surfaces.
Locking the differential by switching the front handle to the rear position is best on roads characterized by increased slipperiness. This measure will give Niva stability. It is worth understanding that after overcoming the problem area, the handle will need to be returned to its original position.
As noted earlier, downshift should be activated before a potential obstacle, but not while the car is already stuck.
It is worth understanding that activating the lock when the vehicle is stationary is sometimes impossible, even if the clutch is depressed. This may be caused by the clutch teeth hitting the gear teeth. In this case, you can try to activate the lock by starting to drive slowly and make a slight turn. If problems arise with disabling the lock, it is recommended to perform the same procedure with the clutch depressed and the steering wheel slightly rocked.

A series of downshifts

You can often encounter the following type of misconception: switching the rear handle can increase the power characteristics of the motor. But this is not true. It serves to change the gear ratio between the engine and the wheels. By increasing it, the traction forces on the wheels will increase. There is also a reduction gear in the dispensing mechanism.

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Its operation can be controlled using the rear handle. When we shift the lever back, we will have a gear ratio of 2.135 - this is a low gear. It is recommended to downshift such a gear only when the car is stationary and the clutch is depressed. Despite the fact that the manual does not contain such a restriction, novice and inexperienced Niva drivers are not recommended to switch while driving, since the Niva transfer mechanism is not equipped with a synchronizer.

Design and principle of operation of the Niva 2121 transfer case

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: How does the transfer case work on a Chevrolet Niva?

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.

Housing Differential housing Shafts Couplings Seals Pinions Gears Flanges Levers

How to turn on all-wheel drive

Since the drive on the Niva is constantly all-wheel drive, the question of how to turn on the all-wheel drive on the Niva Chevrolet means how to turn on the center differential lock.

You need to use blocking in the following cases:

when driving in difficult terrain where there is a danger of wheel slipping;
when there is a lack of engine thrust;
when driving on a road covered with snow or ice.

The main component of the axle locking mechanism is the transfer case. The transfer case is controlled by one six-position lever. The longitudinal stroke provides higher and lower gear rows. Transverse - responsible for locking the center differential. When the lever is in lock mode, a yellow icon lights up on the instrument panel.

The main purpose of the Niva 2121 transfer case

The transfer case (another name is the range multiplier) is connected directly to the gearbox, participates in the distribution of rotation on the axis of the all-terrain vehicle and helps to increase the torque when transmitted to the wheels of the vehicle.

Niva 2121 transfer case cross-sectional diagram

It is necessary to list the main reasons why the RK failed on a Chevrolet. The most common is frequent driving of a given vehicle at high speeds, which negatively affects the working life of the component parts of the box. In particular, the seals may wear out and the fastenings may become loose.

The transfer case is noisy. To solve this problem, you can buy special silent levers for the RK. Thanks to this, the necessary noise insulation is achieved and vibrations will not be noted.

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 the VAZ-21213 model; 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. The effect is achieved by changing the mounting location of the front axle gearbox, which in the modernized version is suspended at a distance from the engine on rubber supports. This approach makes it possible to reduce to a minimum the reactive torque in the longitudinal-vertical direction and the noise level at speed.

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.

Transfer case control

The Niva 2121 transfer case has manual control with a lever-type mechanical drive. The shift lever swings in the longitudinal direction and is performed on an axis that is installed in the bracket eyes in front of the transfer case. Friction is reduced by pressed plastic bushings into the holes of the lever.

The lower part of the lever is inserted into a groove on the rod, and fixation occurs using a figured spring. The other end of the rod, in turn, is connected to a fork, which moves the shift clutch. The rigidity of this connection is ensured by the bolt. The rod at the outlet of the transfer case is sealed with an oil seal, and dirt and dust are protected with a rubber corrugation. The entire switching drive is fixed in the set position by a spring-loaded ball that fits into special grooves in the rod.

How to disassemble the gearbox of a VAZ 2121 Niva 2131

After the box is removed from the car, you can begin disassembling it, which is performed to replace failed elements. To disassemble the gearbox on a VAZ 2121 and Niva 2131, prepare a standard set of tools and perform the following sequence of actions:

Having removed the box, drain the oil from the crankcase, after which we disassemble the clutch release mechanism.

From the toe of the secondary shaft, having unscrewed the fastening nut, press the flange of the elastic coupling.
Next, use a twenty-two key to unscrew the reverse light switch from the box body.
Remove the gear selector mechanism, and then disassemble it if necessary.

Now we need to remove the gearbox housing cover. To do this, use a ten-point socket to unscrew the ten nuts securing the cover. Remove the nuts and washers located underneath them.
Remove the cover and the sealing gasket located under it.

Unscrew the inner nut securing the rear gearbox cover. To do this, move the fork rod of the first and second gears down, resting a screwdriver on the rod through the hole in the gear selection mechanism. When the rod moves, second gear will engage.
And use a thirteen key to unscrew the nut securing the cover.
Remove the cover and bearing of the fifth gear and reverse gears.

Remove the rear bearing thrust ring from the secondary shaft.
Now you can remove the outer ring of the bearing along with the cage and rollers.

Now remove the inner ring, spacer sleeve and oil flinger from the shaft.

To remove the shafts, they must be locked by engaging the appropriate gears. The second gear was engaged before removing the rear cover of the box, and to engage the fifth or reverse speed, use a ten key to unscrew the bolt securing the fork to the rod, then press the fork with a screwdriver and move it down, thereby engaging the reverse gear.

Now that the shafts are locked, use a 17mm spanner to unscrew the bolt securing the fifth gear and reverse gear block, and then remove the bolt and gear block.
Secure the block in a vice with pads made of soft material and press the inner bearing ring off it.

Next, remove the fifth gear bushing, gear with synchronizer blocking ring, and hub from the shaft.

Immediately remove the synchronizer coupling from the shaft.
Then we turn the fifth gear and reverse fork towards the secondary shaft and remove the reverse gear intermediate gear.
Remove the transmission clamps.

Now that the gears and bushings have been removed, we remove the rod and its fork from their seat. Then remove the plug itself from the stem.

The locking block must be removed from the hole in the box housing. To do this, use a magnetized screwdriver.
Next, remove the reverse driven gear from the secondary shaft.

Having removed the gear, we remove the locking key from the groove on the shaft and move it to the side so as not to lose it.
Using a ten-point socket, unscrew the bolt securing the fork to the third and fourth gear rod.

We take out the rod and remove the locking block from it.

Next, using a magnetized screwdriver, remove another locking block located in the groove between the sockets of the first and second, as well as the third and fourth gears.
We also use a socket to unscrew the bolt securing the fork to the rod of the first and second gears. And take out the rod.

Now we need to remove the secondary shaft intermediate bearing retaining plate. To do this, use an impact screwdriver to unscrew the three screws that secure it. Remove the screws and the special lock washers located underneath them.

Remove the locking plate.
Using a 19mm spanner, unscrew the nut securing the reverse idler gear axle. At the same time, we keep the axis itself from turning with a twenty-four key.
We take out the axle.
Remove the clutch housing.

Remove the spring washer from the input shaft.
Now we need to remove the countershaft front bearing clamp washer. To do this, secure the input shaft in a vice through soft metal spacers and use a nineteen key to unscrew the bolt securing the clamping washer.

Remove the bolt and washer.
Now you can remove the bearing. To do this, use two flat screwdrivers to pry it up and remove it.

After removing the bearing, its rear ring may remain on the shaft. If the ring remains, use two flat screwdrivers to press it off the shaft.

Remove the rear ring and thrust ring.

Now we need to remove the rear shaft bearing. To do this, insert a flat-head screwdriver between the end of the bearing and the first gear gear of the intermediate shaft, and move the bearing.
And we take out the outer ring with the separator and rollers and its inner ring.

We move the intermediate shaft a little back and remove it from the gearbox housing.

Remove the input shaft. Using two flat-head screwdrivers, hook it on its rear bearing and pull it slightly towards you, and pull it out of the box body.
If necessary, disassemble the input shaft.

Now remove the needle bearing from the front end of the secondary shaft.
Next, remove the shift forks for 1st and 2nd gears, as well as 3rd and 4th gears.

Remove the secondary shaft intermediate bearing. To do this, use two flat screwdrivers to pry it by the mounting ring.

Tilting it slightly to the side, we pull the secondary shaft out of the box body. If necessary, disassemble it.

At this point, the repair work on disassembling the gearbox on the VAZ 2121 and Niva 2131 has been completed. Make the necessary repairs, then reassemble in reverse order.

Possible problems

During the operation of off-road vehicles, parts and components of the transfer case gradually become unusable due to wear. Most often, the following interruptions in the operation of the mechanism occur:

The front axle does not engage.
The transfer case is overheating.
Leaks and increased oil consumption of the transfer case.
Unauthorized disabling of the front axle.

Harsh operation and insufficient attention to how to use the transfer case on the Niva 2121 lead to the appearance of:

Vibrations in the body while moving Vibrations when starting Hum Noise when maneuvering Tight switching on modes

Also interesting: Chevrolet Niva gearbox diagram video

Experience shows that the culprits are: insufficient oil level, incorrect centering of the steering wheel, loosening of the support fastenings and damage to the rubber bands. An additional influence is exerted by the condition of the cardan and the engine itself.

Vibrations in the body while driving
Vibrations at start
Gula
Noise when maneuvering
Tight switching modes

VAZ 2131 gearbox repair

Is your Niva's transmission starting to fail? The situation is not pleasant: it becomes uncomfortable to drive, and safety on the road remains in great doubt. We will talk about the reasons for the failure of transmission elements another time. Now let’s try to figure out what to do in fact: change the box or repair it.

Repair of VAZ Niva and Niva Chevrolet gearboxes - 2000 rubles.
Remove the box and put it on - 2000 rubles.
Exchange of manual transmission Niva and Niva Chevrolet - 4,000 rubles. (if the body is intact)
Repair with our spare parts and installation - 6,000 rubles. (if the body is intact)
Buy a gearbox - 6,000 rubles.

Replacing Niva Chevrolet boxes is a service that is quite in demand. There are objective reasons for this. And not necessarily caused by breakdowns of the transmission unit. For example, a gearbox is often replaced from a 4-speed to a 5-speed, and the Niva gains a significant advantage in functionality.

If we are talking about a faulty box, there are two traditional options. The first is repair (professional, high-quality, performed in a workshop). The second is replacing the transmission unit. Prices for Niva Chevrolet gearboxes vary widely. This is due to the range of offers and the type of units sold. What is more profitable: repair or replacement?

Also interesting: Working clutch cylinders for Chevrolet Niva in Balashikha