Niva's gearbox is a mechanical unit with manual control, which is equipped with five forward ranges and one rear counterpart. All positions are synchronized with each other, the model is unified with the VAZ-2107 version. Consider the features of this block, as well as how to remove and install it.
The Niva gearbox housing includes the following elements:
- clutch housing;
- similar gearbox compartment;
- back cover;
- fixing mechanisms.
The specified parts are cast from aluminum alloy, the joints are sealed with cardboard gaskets and treated with a hermetic composition. Additional body fins improve heat dissipation. The lower part of the crankcase is protected by a stamped steel flap, the main fastening is carried out by means of bolts to the cylinder block. The alignment of the crankshaft axes with the primary counterpart guarantees centering with a pair of bushings,placed in special holes in the block and crankcase. The rear cover is supplemented with a third motor support, which is fixed to the cross member and the floor of the body by means of welding seams.
Niva's gearbox housing on the left side is equipped with a filler neck, there is a drain analogue at the bottom. The holes are blocked with taper-type threaded plugs. The drain compartment is equipped with a magnet that traps metal particles that enter the oil due to wear of parts.
A breather is screwed into the top of the crankcase, preventing pressure build-up in the gearbox during excessive heating. If this element is defective, active leakage of lubricant through the seals may occur. In this case, the parts dry out, which increases the wear of the components.
1. retraction spring; 2. locknut; 3. adjusting element; 4. cotter pin; 5. fork; 6. pusher; 7. fixing bolt; 8. working cylinder.
There are three shafts in the Niva gearbox:
- The primary roller is supported by a pair of bearings located at the end of the crankshaft and at the front of the gearbox. In addition, a needle bearing is located at the back, serving as a support for the shaft and guaranteeing the alignment of the elements.
- The second shaft also aggregates with a ball bearing in the rear crankcase compartment and a roller analogue on the cover.
- The intermediate analogue interacts with two bearings, and also relies on the roller in the rear flap of the mechanism. Ibidintermediate axle fixed.
Primary and intermediate shafts
The primary roller is equipped with a pair of toothed rims, one of which is located at the front wall of the housing, engages with the front gear. The spur counterpart refers to the 4th gear synchronizer crown, which is why this position is often referred to as "straight".
On the intermediate and secondary shaft there are driven and driving gears that engage with the elements of the corresponding gears. The driven toothed element is rigidly fixed on the shaft by means of a key. Spur gears are directed towards "their" synchronizer. An elastic coupling flange is fixed on the back of the secondary roller. As an additional sealant, they put an additional washer or apply an anaerobic composition.
This part of the Niva gearbox includes in its design: a rigidly fixed hub, a sliding type clutch, a retaining and blocking ring, a spring with a washer. Hubs 3-4 and 1-2 gears are placed internally in the grooves of the secondary shaft, and a similar part of the fifth speed is fixed with a key identical to the fasteners of the driven rear gear.
The outer part of the hubs is equipped with splines that serve to move the sliding sleeves. The last elements have machined sockets, which include the fork parts of the gear adjustment rods. The locking rings are connected by internal rims to the heads of the synchronous gears of the corresponding gears, they are pressed by springs in the directionslip clutches. The spring mechanisms are supported on the plane of the driven gears by means of special washers.
This device in the domestic Niva-21213 gearbox is equipped with a guide plate element with eight rectangular sockets, washers, a shift lever, a reinforced frame and a locking bracket. These constituent components are tightened with three bolts to the box cover at the rear. The neutral position is set by setting the lever between 3 and 4 speeds. The final fixation is carried out using spring bars acting on the lever below.
Thanks to the bent petal type of the bracket, accidental activation of reverse gear instead of fourth gear becomes impossible. To turn on the reverse speed, the Niva gearbox lever is moved to its lowest position, its protrusion should fall below the bracket petal. This design feature improves traffic safety.
1. flange nuts; 2. collar; 3. the clutch is elastic; 4. suspension cross member.
Other parts and mechanisms
Among other elements of the node under consideration, the following devices can be noted:
- Reverse motion transmission. It does not have a synchronizer, activation is carried out by introducing an intermediate gear with a leading analogue of the output shaft and the same part on the intermediate roller.
- The Niva-2121 gearbox has a control drive consisting of three rods,aggregating with forks. The last elements are placed in the sockets of the slip clutches, and the analogue of the reverse gear is placed in the undercut of the intermediate gear.
- The lubrication mechanism provides for the processing of assembly parts by spraying. The shafts are sealed with oil seals, on the secondary shaft of the fifth gear there is an oil deflector in the form of a washer. Filled oil level should reach the lower edge of the filler hole.
Removing the Chevrolet Niva gearbox
At the initial stage, the vehicle must be placed on a viewing ditch or lift. Stops are placed under the wheels and the bridge, the drive is raised from one or both sides. The "handbrake" is released, the gearshift lever is set to the neutral position. The cables are disconnected from the battery.
Further actions are as follows:
- They remove the mat from the floor and the outer covers from the transfer case and gearbox levers, dismantle the hatches and seals, unscrew the handles from the levers.
- Press the lever rod with a suitable tool, remove the locking sleeve from the groove, remove the rod.
- Unhook the tube hanger and mufflers from the receiver.
- Disconnect the fixing clamp, unscrew the mufflers with a spanner wrench, after which the pipe is removed by moving down.
- Unscrew the lower screws of the clutch housing and the wire going to ground, as well as the wiring of the "stops".
- Dismantle the retractable spring mechanism of the clutch release fork, remove the pusher cotter pin.
- From crankcasedisengage the slave cylinder. At the same time, the last element is left in place to prevent leakage of brake fluid with further pumping of the hydraulic drive.
Finishing steps for removing the Chevy Niva gearbox and installing
The further process consists of the following steps:
- A clamp is put on the elastic coupling, followed by tightening. This will make it easier to remove and reinstall the coupling. Unscrew the lock nuts and rotate the intermediate cardan while removing the fasteners of the output shaft flange.
- Disconnect the speedometer flexible roller from the drive on the "razdatka".
- Disconnect the flanges of the cardan shafts of the distributing unit, lower the shafts with further withdrawal towards the analogues of the axle drives.
- Unscrew the fixing bolts of the body brackets, and then remove the transfer case together with the propeller shaft.
- Unscrew the bolt fastener of the starter to the clutch housing with the end hinged tool, repeat the same procedure with the bolts on the cover of this assembly.
- Disengage the rear engine mount and cross members, after which the last element is dismantled, holding the gearbox from below.
- Under the crankcase part of the mechanism substitute a jack or other reliable support. The fixing bolts are unscrewed with a wrench, the gearbox is removed together with the transmission housing. In this case, the block is shifted to the rear of the vehicle, which will allow the primary roller of the gearbox to be removed from the front bearing and the hub of the driven disktransmission.
- When carrying out work on the removal or installation of the gearbox, do not rest the edge of the input shaft on the flange-stop of the pressure spring. This is fraught with deformation of the connecting plates of the clutch block.
The installation of the Niva-21214 gearbox is carried out in a mirror order. It is first necessary to apply a special grease of the Litol-24 type to the splined edging of the shaft. You also need to center the clutch driven mechanism by editing.
At first glance, the Niva-2131 gearbox is a complex and high-tech mechanism. By and large, this is true, especially if a person does not have experience in disassembling and assembling such nodes. Nevertheless, knowing the sequence of actions, as well as the structure of the part, it is quite possible to replace problematic spare parts and repair the specified element on your own using a minimal set of tools. If you are unsure of yourself, it is better to consult a specialist so as not to aggravate the situation.