Warning. If the synchronizer blocking rings are in good condition, mark them during disassembly in order to subsequently install them in their original places.
Disassembly
1. With two mounting blades, slightly raise the inner ring of the roller bearing.
2. We introduce the grips of the puller into the resulting gap.
3. We press the inner ring of the roller bearing from the secondary shaft.
4. With special tongs, open the retaining ring.
5. Remove the retaining ring from the gearbox output shaft.
6. With a puller, we compress the final drive gear.
Remove the main gear from the shaft.
7. Remove the driven gear of the first gear from the secondary shaft...
... as well as the first gear synchronizer blocking ring.
8. Using tongs, open the retaining ring of the first-second gear clutch hub...
...and remove the circlip.
9. Press two mounting blades from the secondary shaft and remove...
... a hub with a first-second gear clutch...
...second gear synchronizer ring...
...and the second gear driven gear.
10. From the other end of the secondary shaft, press the puller...
...and remove the ball bearing.
11. Remove the thrust washer.
12. Remove the driven gear of the fourth gear.
13. Remove the fourth gear synchronizer blocking ring.
14. Unclench with tongs and remove the retaining ring of the third-fourth gear clutch hub.
15. Putting stops under the gear of the third gear, with a hammer through a wooden gasket, we press out the output shaft from the coupling hub.
16. Remove the hub with the sliding clutch from the secondary shaft.
17. Remove the third gear synchronizer blocking ring.
18. Remove the driven gear of the third gear.
19. If it is necessary to replace parts of the gear shift mechanism, remove the sliding clutch from the hub (do not lose the springs and cracker balls).
Assembly
When assembling the synchronizer, it is necessary to correctly align the hub and sliding sleeve. Notches are made in the places where the crackers are installed in the slots of the coupling.
Crackers in the grooves of the coupling hub must be installed with lateral protrusions outward.
Blocking rings of the synchronizer of the first, second and third gears with three tides on the outer surface...
... and the synchronizer of the fourth and fifth gears - with six tides.
We assemble the gearbox output shaft in the reverse order of disassembly. Lubricate the friction surfaces of parts with clean gear oil. After assembling the secondary shaft, moving the sliding couplings, we are convinced of their operability and reliable fixation in the middle and extreme positions.