Disassembly and assembly of the gearbox (Chevrolet Niva 1)

Disassembly. Wash the gearbox and install it on the stand. Drain the oil and remove the lower cover with the gasket.

Remove the clutch release fork and the clutch release sleeve assembly from the guide sleeve of the front gearbox cover.

Remove the clutch housing with the gasket and the front cover of the gearbox together with the oil seal and spring washer (see figure 3-9).

Unscrew the reversing light switch, being careful not to deform its housing.

Remove the bolt securing the shift fork for the third and fourth gears. Install the 41.7816-4070 locking pin on the primary shaft or engage two gears simultaneously. This will prevent the primary, secondary and intermediate shafts from turning and will allow subsequent disassembly operations to be performed.

Unscrew nut 28 (see figure 3-7) several turns to move the centering ring 30 of the elastic coupling, and tighten the nut 28 again. Use a puller to remove the centering ring of the elastic coupling of the cardan shaft from the end of the secondary shaft (figure 3-10).



The black arrows indicate the nuts that secure the clutch housing to the gearbox; the white arrow indicates the hole in the front cover for releasing oil from the gearbox housing to prevent the clutch discs from becoming oily.





Remove the seal 29 of the centering ring of the elastic coupling from the end of the secondary shaft, unscrew the nut 28 and remove the flange of the elastic coupling using a puller (figure 3-11).

Before removing the rear cover, remove the gear selector mechanism. To do this, remove the drive rod clamp 33 (see figure 3-8), unscrewing bolt 34. Then, unscrewing fastening nuts 21 (see figure 3-7), remove the gear selector mechanism assembly.

Unscrew the six nuts securing the rear cover 36, and one of the nuts securing the rear cover is unscrewed from inside the gearbox housing with the lower cover removed. When removing the rear cover, it must not only be fed back, but also turned to prevent it from touching the reverse gear block and fifth gear.



After removing the inner ring of the rear bearing 32 and the spacer sleeve 33 of the bearing from the secondary shaft, loosen the bolts securing the cover of the retainers 5 (figure 3-12) and unscrew bolts 2 and 4 securing the gear block and the fifth gear and reverse gear engagement fork. Remove oil deflector washer 26 (see figure 3-7) and remove rod 1 (figure 3-13) from fork 2. At the same time, the spacer sleeve 3 is removed from the rod. Then remove the gear block 4 from the splines of the intermediate shaft.



Remove intermediate gear 1 at the same time (figure 3-14) reverse gear from the axle, gear 3 assembled with the clutch and fork 4 from the secondary shaft. Then remove the thrust washer and retaining ring.







Remove hub 4 (figure 3-15) synchronizer of the fifth gear, spring washer and driven gear 2 of reverse gear.





Using shaped mandrels and rod punches, remove the front and rear intermediate shaft bearings from the gearbox housing. Mark the inner rings of the double-row bearing with the help of which you install these rings in their previous places in the outer ring of the bearing.

Remove the intermediate shaft from the gearbox housing by tilting it as shown in Figure 3-16.



Remove the shift fork rods of the first, second, third and fourth gears from the gearbox housing one by one, after first unscrewing the fork mounting bolts. While removing the rods, simultaneously remove the three locking crackers 6 (figure 3-17). Remove the locking plate (figure 3-18) intermediate bearing of the secondary shaft. Unscrew the nut securing the axle of the intermediate reverse gear gear and remove it.







The arrow shows the direction of the impact stroke of the screwdriver clip when struck with a hammer.



Using drifts, remove the primary shaft together with the bearing and synchronizer ring (figure 3-19) and remove the needle bearing from the front end of the secondary shaft.



Knock the secondary shaft out of the intermediate bearing, remove the intermediate bearing and, tilting it as shown in Figure 3-20, remove the secondary shaft from the crankcase complete with gears, couplings and synchronizer rings. Remove the synchronizer coupling of III and IV gears from the shaft.



Disassemble the primary shaft (figure 3-21):

• remove the retaining ring 7, the locking ring 6 and the synchronizer spring 5;
• install the shaft on the press and, having compressed the spring washer 2 with the mandrel 41.7816-4069, remove the retaining ring 1, and then the spring washer and bearing 3.

Disassemble the secondary shaft (figure 3-22):

• remove gear 11 of the first gear with sleeve 12, hub 3 with sliding clutch 4 for switching 1st and 2nd gears, gear 10 of the second gear together with locking ring 5 of the synchronizer from the rear side of the shaft;
• install the secondary shaft with the mandrel 41.7816-4069 on the press (figure 3-23), place support half rings 3 under the third gear pinion and, pressing the mandrel onto the spring washer, remove the retaining ring 2, then the spring washer 4, the hub of the sliding clutch for switching third and fourth gears and the third gear pinion.

If necessary, disassemble the gear selector mechanism (figure 3-24), for what:

• remove protective covers 1 and 6 (figure 3-25);
• pull the housing of the traction joint 3, squeezing the retaining ring 15, from the gear selection lever 13.

This will allow you to remove the hinge pin of the rod 2 and remove the drive rod 5 with two bushings 4

• remove spring 21 and spherical washer of ball joint 22 from gear selection lever 13;
• visually mark the location of the parts relative to mark A (see figure 3-24), applied to the guide plate to ensure that the parts are connected in the same position during assembly;
• after unscrewing the nuts from the mounting bolts, separate the parts of the gear selection mechanism and remove lever 16, its ball joint 4 and sealing rings 19.

Also, if necessary, disassemble the gear selection mechanism control drive, for which:

• remove protective cover 12 (figure 3-26), remove the reverse gear lock lining 24 from the lever housing by unscrewing the two bolts 25;
• disassemble the gear selector lever housing by unscrewing four bolts 35;
• remove the ball joint housing 1 by unscrewing the three nuts 37. Then unscrew the nut 23, remove the gear selection lever shaft 15 and remove the tie rod end 13;
• to remove the ball joint slider 3, remove the retaining ring 4.

Assemble the gearbox in the reverse order of disassembly. Please note that:

• the reverse intermediate gear shaft is secured before installing the shafts in the gearbox housing with a torque of 70...80 Nm (7...8 kgf·m);
• before installing the fifth gear and reverse gear fork rod into the crankcase, install a spacer sleeve on it;
• the inner bearing ring is pressed onto the fifth gear and reverse gear block, and the outer one is pressed into the rear cover socket;
• the secondary shaft rear bearing is pressed onto the shaft to facilitate installation of the rear cover;
• intermediate gear 1 (see figure 3-14) reverse gear, gear 3 and fork 4 install simultaneously;
• tighten the gear block mounting bolt to a torque of 70.80 Nm (7.8 kgf·m);
• before installation, coat the working surface of the seals with Litol-24 grease;
• when installing seals and bearings, use mandrels 41.7853-4028, 41.78534032, 41.7853-4039;
• when assembling the gear selection mechanism, apply Litol-24 or LSC-15 grease to the surfaces of the gear selection lever that contact the ball joint and the traction joint housing. Also apply grease to the inner surface of the spherical washer of the ball joint;
• when assembling the gearshift control drive, apply LSC-15 grease to the inner surface of the ball joint housing;
• when installing the gearshift control drive, holding the gearshift lever and the support plate in a relative position determined by the dimensions (see figure 3-9) D= (1.5+0.5) mm, E=(1+0.5) mm and W=(81.5+0.5) mm, tighten the control drive rod clamp bolt to a torque of 16...25 N·m (1.6...2.5 kgf·m);
• when installing the gear selector handle, ensure that it is positioned relative to the direction of travel of the vehicle as shown in Figure A (figure 3-27).