Disassembly and assembly of the gearbox

Disassembly

Rinse the gearbox and install it on the stand. Drain the oil and remove the bottom cover with gasket.

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

Remove the clutch housing with gasket and transmission front cover (complete with seal and spring washer) (pic. 3-15).



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

Turn out a bolt of fastening of a plug of switching of III and IV transfers. Install clamp 41.7816.4068 on the input shaft or simultaneously engage two gears. This will prevent rotation of the input, output and countershafts and allow subsequent disassembly operations.

Remove the retaining ring from the end of the output shaft of the gearbox (pic. 3-16).




After unbending the lock washer, loosen the nut a few turns to move the centering ring of the elastic coupling, and tighten the nut again. Using A.40006/1 ejector with A.40005/4 puller, remove from the end of the secondary shaft the centering ring of the flexible coupling of the cardan shaft (pic. 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 with a puller A.40005/3/9B/9C (pic. 3-18).




Remove the gearbox rear cover by unscrewing its fastening nuts and screw 4 (pic. 3-19) limiting the transverse travel of the lever, as well as moving the growl to the left: shifting gears to free it from the gear shifting rods.



Remove the rear bearing from the output shaft and then the bearing spacer.

Remove the fork with spacer from the reverse gear rod, and the reverse idler gear from the axle.

Remove the reverse gear retaining ring from the countershaft (pic. 3-20); Remove gear and spring washer.



Remove the circlip of the reverse driven gear from the secondary shaft, pressing the spring washer with a mandrel 41.7816.4069 to relieve the load from the circlip. Remove the reverse driven gear and spring washer.


With the help of curly mandrels (screwdriver type) and rod drifts, remove the front and rear bearings of the intermediate shaft from the gearbox housing. On the inner rings of the double-row front bearing, put marks on which these rings should be installed in their original places in the outer ring of the bearing.

Remove the intermediate shaft from the gearbox housing. tilting it as shown in Figure 3-21.



Remove cover 20 (pic. 3-22) rod clamps together with the gasket, remove the rod 18 of the reverse gear fork, the rod 17 of the shift fork of III and IV gears from the gearbox housing. Turn away a bolt of fastening of a plug of I and II transfers, take out a rod and plugs. When removing the rods, simultaneously remove the three blocking crackers 19. Remove the lock plate (pic. 3-23) intermediate bearing of the secondary shaft and the axis of the intermediate reverse gear.






With mandrels (screwdriver type) remove the input shaft together with the bearing and synchronizer ring (pic. 3-24) and remove the needle bearing from the front end of the output shaft.



Knock out the secondary shaft from the intermediate bearing, remove the intermediate bearing and, tilting as shown in fig. 3-25, remove the output shaft assembly with gears, clutches and synchronizer rings from the crankcase. Remove the 3rd and 4th gear synchronizer coupling from the shaft.



Disassemble the input shaft (pic. 3-26):

• remove the retaining ring 7, blocking ring 6 and synchronizer spring 5;
• install the shaft on the press and, compressing 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 output shaft (pic. 3-27):

• remove from the rear side of the shaft gear 121 - gears with sleeve 13, hub 3 with a sliding clutch for switching I and II gears, gear 11 of the second gear together with blocking ring 5 of the synchronizer;
• install the secondary shaft with mandrel 41.7816.4069 on the press (see fig. 3-28), place support half rings 3 under the gear of the III gear, and, pressing the mandrel on the spring washer, remove the retaining ring 2, then the spring washer 4, the hub of the sliding clutch of the III and IV gears and the gear of the III gear.

Disassemble the shift lever and rear cover:

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

Assembly

The assembly of the gearbox is carried out in the reverse order of disassembly. In doing so, keep in mind that:

• spring 22 (pic. 3-22) the reversing fork rod retainer ball differs from others in elasticity, it is painted green or has a cadmium coating, and since 1985 it has been black oxidized;
• when installing the clutch housing with the front cover of the gearbox, the hole in the front cover must be located as shown in fig. 3-15;
• before installation, cover 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 bearings and shaft seals, use mandrels 41.7853.4028, 41.7853.4032, 41.7853.4039.