Disassembly and assembly of the gearbox (5-speed)

Crankcase of a mechanical five-speed gearbox

Removing the cover of the five-speed gearbox

The arrow shows the location of the spring locks for holding the engaged gear.

Disassembly

1. Remove the release bearing and clutch release forks.

2. Remove the four bolts securing the clutch housing to the front of the transmission housing.

3. Remove the O-ring from the rear of the gearbox housing (tool 21.051).

4. Remove the ring from the rear of the gearbox housing (tool 16.025).

Attention! This ring can only be replaced together with the rear of the gearbox housing and output shaft (set).

5. Remove the front cover of the gearbox housing.



6. Engage 1st gear and knock out the selector mounting pin.



7. Remove the plate, spring and pin of the 5th gear spring lock.

8. Remove the rear of the gearbox housing.

9. Insert one bolt to hold the middle section of the gearbox housing in place.

10. Unscrew the bolt and pin of the spring lock of the selector axis.

11. Remove selector shaft.

12. Remove the fork assembly, selector and spring locks.



13. Remove the 5th gear synchronizer circlip on the output shaft and move the entire synchronizer back.




14. Engage two gears at the same time (to lock the gearbox) and unscrew the nut securing the 5th gear on the intermediate shaft.

15. Using a rod, press back the axle of the intermediate shaft gear assembly. It is necessary to maintain constant contact of the rod with the axis of the intermediate shaft gear unit in order to prevent the bearing needles from falling out.

16. Attach the tool to the front of the gearbox housing.



17. Remove the 5th gear from the countershaft using tool 16.033

18. Reinsert the pinion shaft of the countershaft into its original place by pushing out the shaft of special tool 16.033 by hand.

19. Remove the retaining ring from the gear block bearing in the middle of the gearbox housing.


20. Remove bearing spacer.

21. Disable both previously engaged gears.

22. Unscrew the bolt holding the middle part of the gearbox housing by 6 - 7 mm and move the middle part of the crankcase.



23. Press the gear cluster bearing into the middle of the crankcase using two thin screwdrivers (1 and 2) and remove the bearing outer ring (3 - bolt).

24. Move the axle of the gear cluster back enough to allow the gear cluster to be removed from the crankcase.

25. Lay the countershaft gear assembly on the bottom of the front of the gearbox housing.

26. Remove the clutch release bearing guide and remove the input shaft.

27. Remove the output shaft together with the middle part of the crankcase.

28. Using a suitable puller (large diameter bushing, M8Ch60 bolt with nut) remove the reverse gear shaft.

29. Remove retaining ring and reverse gear lever shaft.

Assembly

1. Before assembly, wash and check the condition of bearings, synchronizers and gears.

2. The assembly of the gearbox is carried out in the reverse order with respect to the process of its disassembly. During installation, pay attention to the following steps.


3. Lubricate the countershaft gear assembly bearing needles with bearing grease and correctly position them on the axis that forms the inner raceway.



4. Using special tool 16.033, install the 5th gear on the intermediate shaft. The spacer sleeve on the gear side must be coated with grease to ensure that the gear rotates freely.

5. The threads of the bolts screwed into the through holes of the crankcase should be coated with an appropriate sealant before installation.

6. Before tightening the rear of the gearbox housing, check the operation of the gearbox (the possibility of switching on individual gears and free rotation of the shafts).