Disassembly and assembly of the gearbox (VAZ-2121)

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, from the guide sleeve of the front gearbox cover, the clutch assembly with the bearing and connecting spring.

Remove the clutch housing with gasket and front gearbox cover (together with the seal and spring washer) (Fig. 3-15).



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 locking pin 41.7816.4068 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.

Remove the retaining ring from the end of the transmission secondary shaft (Fig. 3-16).





After straightening the lock washer, unscrew the nut a few turns to move the centering ring of the elastic coupling, and tighten the nut again. Using the ejector A.40006/1 with the puller A.40005/4, remove the centering ring of the elastic coupling of the cardan shaft from the end of the secondary shaft (Fig. 3-17).



Remove the seal of the centering ring of the elastic coupling with the spring from the end of the secondary shaft, unscrew the nut and remove the flange of the elastic coupling using the A.40005/3/9B/9C puller (Fig. 3-18).




Remove the rear cover of the gearbox by unscrewing its fastening nuts and screw 4 (Fig. 3-19) for limiting the lateral travel of the lever, and also by moving the gear shift lever to the left to release it from the gear engagement rods.



Remove the rear bearing from the secondary shaft, then the bearing spacer sleeve.

Remove the fork with the spacer sleeve from the reverse gear engagement rod and the reverse gear intermediate gear from the axle.

Remove the reverse drive pinion retaining ring from the intermediate shaft (Fig. 3-20); remove the gear and spring washer.



Remove the reverse driven gear retaining ring from the output shaft, using the 41.7816.4069 tool to press the spring washer against the retaining ring to relieve the load. Remove the reverse driven gear and spring washer.

Using shaped mandrels (type of screwdrivers) and rod punches, remove the front and rear bearings of the intermediate shaft from the gearbox housing. On the inner rings of the double-row front bearing, apply marks according to which these rings are installed 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 Fig. 3-21.



Remove cover 20 (Fig. 3-22) of the rod retainers together with the gasket, remove rod 18 of the reverse gear fork, rod 17 of the III and IV gear shift fork from the gearbox housing. Unscrew the bolt securing the I and II gear fork, remove the rod and forks. While removing the rods, simultaneously remove three locking crackers 19. Remove the locking plate (fig. 3-23) intermediate bearing of the secondary shaft and the axis of the intermediate reverse gear gear.





Using mandrels (type of screwdrivers) remove the primary shaft together with the bearing and synchronizer ring (Fig. 3-24) 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 Fig. 3-25, 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 (Fig. 3-26):

• 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 (Fig. 3-27):

• remove gear 121 from the rear side of the shaft - gear with sleeve 13, hub 3 with sliding clutch for switching 1st and 2nd gears, gear 11 of the second gear together with locking ring 5 of the synchronizer;
• install the secondary shaft with the mandrel 41.7816.4069 on the press (see fig. 3-28), place support half rings 3 under the third gear pinion and, pressing the mandrel on 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.

Disassemble the gear shift lever and rear cover:

• remove the cuff 19 (Fig. 3-29), the cover 20 of the lever, then the retaining ring 14, the washer 13, the spring 12 and the spherical washer 11;
• unscrew the nuts securing flange 16, disconnect the release spring 3 of the lever from the eye of bolt 1 and remove the lever together with the flange, support 10 and cup 5.

Assembly

The gearbox assembly is carried out in the reverse order of disassembly. Please note that:

• spring 22 (Fig. 3-22) of the ball of the reverse fork rod retainer differs from others in its elasticity, it is painted green or has a cadmium coating, and since 1985 - black oxidation;
• when installing the clutch housing with the front cover of the gearbox, the hole in the front cover must be positioned as shown in Fig. 3-15;
• before installation, coat the working surface of the seals with LITOL-24 grease;
• when installing the reverse gear retaining ring, use drift 41.7816.4069 as shown in Fig. 3-30, and when installing the bearings and shaft seals, use drifts 41.7853.4028, 41.7853.4032, 41.7853.4039.