Disassembly
1. Drain the oil from the gearbox (see "Gearbox - checking the level and changing the oil").
2. Remove the gearbox (see "Gearbox - removal and installation").
3. We clean with a brush and wash the outer surface of the box with kerosene or white spirit.
4. Remove the release bearing clutch and the clutch release fork from the gearbox (see "Clutch parts - removal and installation").
5. Disconnect the flexible coupling of the propeller shaft from the flange on the secondary shaft of the box (see "Cardan gear - disassembly and assembly").
6. Remove the flexible coupling flange from the output shaft of the gearbox (see "Output shaft oil seal - replacement").
7. Disconnect the support of the power unit with the cross member from the rear cover of the gearbox (see "Power unit supports - replacement").
8. Remove the speedometer drive (see "Speedometer drive - replacement").
9. Remove the reversing light switch (see "Reversing light switch - check and replace").
10. Remove the cuff from the ball joint of the gear lever.
11. Key on 10 mm unscrew the three nuts securing the gear lever housing to the rear crankcase cover.
12. Remove the lever body and seal A under it from the studs.
13. socket wrench at 13 mm unscrew the two nuts securing the exhaust pipe bracket of the exhaust system.
14. We remove the bracket and take out the embedded bolt with a four-sided head located under it.
15. Socket and spanner keys at 13 mm unscrew the five nuts securing the rear cover.
16. socket wrench on 10 mm unscrew the ten nuts securing the bottom cover.
17. Remove the cover and the gasket under it.
18. Some nuts come loose with the studs. In this case, washing the threaded holes and studs with a solvent, apply fixing glue according to the instructions and install the studs in place.
19. Key by 13 mm unscrew the remaining rear cover fastening nut located inside the crankcase.
20. To facilitate the removal of the rear cover, use a screwdriver to sink the 1st and 2nd gear engagement rod. This engages the second gear.
21. Tapping the cover with a hammer with a rubber or wooden striker around the perimeter of the mounting plane, disconnect the cover from the box crankcase.
22. Remove the rear cover from the studs, and then, turning it clockwise, remove it from the crankcase. The gasket installed between the cover and the crankcase may break. When assembling, install a new gasket.
23. We remove the plastic plug of the gear unit of the V gear and reverse gear from the back cover by squeezing it out with a suitable tool through the hole in the bearing.
24. Using pliers, remove the thrust ring of the bearing of the gear unit of the V gear and reverse gear from the groove in the cover.
25. In order not to damage the back cover, we install it on two wooden bars and a hammer (through a suitable mandrel) we press out the bearing of the gear block of the V gear and the reverse gear. The inner ring of the bearing usually remains on the block shaft.
26. We take out the bearing.
27. We remove the output shaft seal from the hole in the rear cover (see "Output shaft oil seal - replacement").
28. We take out the thrust washer of the inner ring of the rear bearing of the secondary shaft.
29. With a mandrel suitable in diameter, we press out the rear bearing of the output shaft and remove it.
30. Remove the inner ring of the rear bearing from the secondary shaft.
We assemble the bearing by tying its parts with wire or twine.
31. Remove the speedometer drive gear and the ball - gear retainer A, located in the groove of the shaft.
32. Remove the oil slinger.
33. Key by 10 mm we unscrew the bolt of fastening of the fork of inclusion of V transfer and reverse gear.
34. To block the rotation of the shafts, we shift the intermediate gear A of the reverse gear, including the reverse gear. The second gear was included earlier, when removing the back cover. If it turns off, press the rod B. With a socket wrench by 17 mm loosen the bolt securing the gear unit of the 5th gear and reverse gear without completely unscrewing the bolt.
35. socket wrench by 13 mm unscrew one nut securing the clutch housing to the gearbox and a socket wrench by 17 mm unscrew the remaining six nuts.
36. Having squeezed out with a screwdriver, we disconnect the clutch housing from the box and remove the sealing gasket.
37. To replace the input shaft oil seal with a punch, we press it out through the hole in the flange of the front cover of the gearbox.
3 8. Use pliers to remove the oil seal from the front cover of the gearbox.
39. Remove the spring ring from the input shaft of the gearbox. The ring has a conical shape and with a smaller diameter is installed towards the bearing.
40. socket wrench by 19 mm unscrew the bolt securing the front bearing of the intermediate shaft and remove the bolt together with the spring and clamping washers.
41. socket wrench by 17 mm finally unscrew and remove the gear block mounting bolt.
42. By shifting the V gear engagement fork along the rod, remove the gear block from the intermediate shaft.
43. We install the gear block in a vise and with two large screwdrivers we press the inner ring of the intermediate shaft rear bearing from it.
We assemble the bearing and tie its parts with wire or twine.
44. Remove the spacer from the secondary shaft.
45. socket wrench by 13 mm unscrew the two bolts securing the cover of the rod clamps.
46. Remove the cover along with the gasket.
47. Remove the rod retainer springs from the holes in the crankcase. The spring A of the detent of the engagement rod of the 5th gear and the reverse gear differs from the others in rigidity. To distinguish it, it has a dark color and during assembly it must be installed in its place.
48. It is more convenient to remove the retaining balls with a rubber pear, creating a vacuum.
49. Remove the V gear assembly with the synchronizer from the secondary shaft.
50. Remove the distance ring.
51. Having shifted the gear shift fork, remove the V gear synchronizer clutch.
52. Holding the fork, remove the reverse intermediate gear from the axle.
53. Remove the V gear and reverse engagement rod together with the gear engagement fork and the remote sleeve A of the rod. We remove the bushing and fork from the stem.
54. socket wrench by 10 mm unscrew the bolt securing the stem head and remove it.
55. Using a magnetic screwdriver or using a rubber bulb, remove the blocking cracker from hole A in the crankcase wall.
56. Using pliers, open the retaining ring of the V gear synchronizer clutch hub and remove it.
57. Remove the hub from the shaft.
58. Remove the spring washer.
59. Remove the reverse gear.
60. Pushing out from the inside, we take out the rear bearing of the intermediate shaft.
61. Using two screwdrivers for the adjusting ring, we take out the front bearing of the intermediate shaft.
62. We take out the intermediate shaft from the crankcase.
63. Prying with two screwdrivers, remove part of the inner ring of the rear bearing from the intermediate shaft and assemble the bearing.
64. socket wrench by 10 mm with an extension, unscrew the bolt securing the fork of the inclusion of III and IV gears to the stem.
65. We take out the third and fourth gear engagement rod from the hole, while removing the fork from it.
66. Remove the blocking cracker from the hole in the rod.
67. With a powerful magnet or with the help of a pear rubber, we remove the blocking cracker from the hole in the crankcase.
68. socket wrench by 10 mm unscrew the bolt securing the fork of the inclusion of I and II gears.
69. We take out the stem from the hole, while removing the fork from it.
70. With an impact screwdriver, unscrew the three screws securing the lock plate of the intermediate bearing of the secondary shaft and remove it.
71. Using two large screwdrivers for the bearing adjusting ring, we push the bearing out of the crankcase.
72. Remove the input shaft assembly.
73. Remove the front roller bearing from the shaft bore. The bearing can remain at the end of the secondary shaft.
74. Using two screwdrivers for the mounting ring of the intermediate bearing of the secondary shaft, we pull the bearing off the shaft.
75. We take out the secondary shaft from the crankcase.
76. Holding the key by 24 mm axis of the intermediate reverse gear against rotation, with a socket wrench by 19 mm Loosen the axle nut.
77. Clamping the secondary shaft vertically in a vice through the soft lining, remove the 3rd and 4th gear synchronization clutch from the shaft.
78. Unclench with tongs and remove the retaining ring of the hub from the shaft.
79. Remove the spring washer.
80. Remove the synchronization clutch hub.
81. Remove the gear with the 3rd gear synchronizer.
82. We support the edges of the gear of the 1st gear on a rigid base (e.g. two keys), up to 5 mm thick. Through a soft metal drift, we press the output shaft out of the gear bushing.
83. We take out the sleeve.
84. Remove the gear with the synchronizer of the 1st gear.
85. We take out the hub of the synchronization clutch of I and II gears.
86. Remove the synchronization clutch.
87. Remove the gear with the 2nd gear synchronizer from the shaft.
88. Having secured the input shaft in a vice through the soft lining, we push the tongs apart and remove the bearing circlip.
89. Remove the spring cup washer.
90. Having rested the edges of the bearing on a rigid base, we press out the input shaft from the inner ring of the bearing through a soft metal drift.
91. Holding the blocking ring of the IV gear synchronization clutch with your hand, push the tongs apart and remove the retaining ring.
92. Gradually releasing the blocking ring, remove it and the IV gear synchronizer spring.
93. Similarly, we analyze the synchronization mechanisms of other transmissions.
Assembly
Note The tightening torques of the critical threaded connections of the parts are given in the appendices (see "Tightening torques for threaded connections").
Before assembly, we wash all parts with white spirit or kerosene and blow with compressed air. Wash and blow out bearings with compressed air. Inspect and replace worn parts. The parts must not show any damage or signs of excessive wear, and the mating surfaces of the parts must not show signs of scuffing.
The crankcase walls must be free of cracks and the bearing housings free from wear or damage. The contact surfaces of the connectors of the gearbox housing, clutch housing and rear cover must not be damaged, causing divergence of the shaft axes and insufficient tightness.
Shafts must not be damaged or excessively worn on working surfaces and splines. Minor surface irregularities can be removed with fine-grained sandpaper; if there are large damages or deformations, the shaft must be replaced with a new one.
Bearings should not show signs of destruction of tracks, cages, balls or rollers, when turning the bearing rings, the rolling should be smooth. When repairing gearboxes with significant mileage (100 thousand km or more) it is advisable to replace all bearings with new ones, regardless of their current condition.
Excessive wear and chipping of gear and synchronizer teeth is not allowed, the working surface of the teeth must be smooth.
Also, deformation of the gear forks is not allowed, the fork rods must slide freely without a significant gap in the crankcase holes.
There must be no signs of seizing on the gear clutch hubs.
The friction surfaces of the blocking rings must be knurled. In case of wear of the notch, the blocking ring is replaced with a new one.
1. We replace all gaskets and seals with new ones.
2. Before installation, grease the working surfaces of the seals with a thin layer of grease.
3. When assembling the gearbox, lubricate all parts with gear oil.
4. When assembling the gear blocks on the shafts, installing the retaining rings, upset them with a screwdriver until the rings are completely fixed.
5. When installing bearings on shafts, we apply force to the inner rings, and when installing in the crankcase holes, to the outer ones.
6. With a suitable mandrel, we press the input shaft oil seal into the front cover.
7. Further assembly of the gearbox is carried out in reverse order. Before installing the box on the car, we check the clarity of the inclusion of all gears.