Preparatory operations
1. Disconnect the hydraulic pump connector.
2. Turn on the ignition and shift gears throughout the entire range until the pressure in the gear shift hydraulic drive system is completely reduced.
3. Disconnect the negative cable from the battery.
4. Drain the oil from the hydraulic drive.
5. Remove any dirt around the gearbox oil drain plug.
6. Unscrew the drain plug (14) and drain the oil from the gearbox.
7. Remove the gearbox.
Gearbox disassembly
8. Remove the guide pins (16).
9. Secure the gearbox to the stand.
10. Remove the flange (2) of the propeller shaft.
11. Remove the output shaft speed sensor (see pp. 12-14).
12. Disconnect the sensor connector (1) (drawing VN 4.011).
13. Unscrew the screw (2).
14. Remove the sensor (3).
VN 4.011. Removing and installing the output shaft speed sensor: 1. Speed sensor connector; 2. Screw; 3. Speed sensor; 4. Sealing ring
15. Remove the oil receiver (see pp. 16-19).
16. Disconnect the ventilation tube (2) (drawing VN 4.012) from the ventilation pipe (3).
17. Turn the ventilation pipe (3) 45° to the right and remove it.
18. Disconnect the pressure sensor connector (5).
19. Remove the clamp (6).
VN 4.012. Removing and installing the oil receiver: 1. Pipeline; 2. Ventilation tube; 3. Ventilation pipe; 4. Sealing ring; 5. Hydraulic drive pressure sensor connector; 6. Clamp; 7. Screw; 8. Screw; 9. Oil receiver
VN 4.013 Removal and installation of the hydraulic pump of the gearbox control drive: 1. Hydraulic pump power supply connector; 2. Outlet pipeline; 3. Hydraulic pump; 4. Receiving tube (oil inlet to the pump); 5. Screw
VN 4.014 Removing and installing steering angle sensors 1. Steering angle sensor connector; 2. Bracket; 3. Screw; 4. Screw; 5. Main shaft rotation angle sensor of the shift mechanism; 6. Gear sensor
20. Remove the hydraulic pump (see pp. 21-24) (drawing VN 4.013).
21. Disconnect the connector (1).
22. Disconnect the pressure pipe (2) from the hydraulic pump (3).
23. Unscrew the screws (5).
24. Disconnect the inlet tube (4).
25. Remove the steering angle sensors (see pp. 26-30).
26. Disconnect the sensor connector (1) (drawing VN 4.014).
27. Remove the rear right screw (3) securing the sensor mounting plate.
28. Unscrew the screws (4).
29. Turn the sensor (5) approximately 45° to the right and remove it.
30. Turn the sensor (6) approximately 45° to the left and remove it.
31. Remove the mounting plate (2) of the steering angle sensors (drawing VN 4.015).
VN 4.015 Steering angle sensor mounting plate: 1. Screw; 2. Steering angle sensor mounting plate
32. Remove the hydraulic block (see pp. 33-40)
33. Disconnect the pressure line from the oil receiver (pressure accumulator).
34. Unscrew the screw (3) (drawing VN 4.016) and remove the coupling sleeve (2) from the main drive shaft (1).
35. Disconnect the clutch control line (4) from the hydraulic unit (5) (drawing VM 4.017).
36. Disconnect the connectors (6) of the solenoid valves.
VN 4.016: 1. Main drive shaft; 2. Connecting sleeve; 3. Screw
37. Remove the return line (7) from the hydraulic block.
38. Disconnect the pressure line (8) from the hydraulic unit (5).
VN 4.017 Removal and installation of the hydraulic unit: 4. Clutch control pressure pipe; 5. Hydraulic control unit of the gearbox; 6. Connectors of electromagnetic valves of the hydraulic unit; 7. Return pipe; 8. Pressure tube
39. Unscrew screws (9) and (10) (drawing VN 4.018).
40. Lift the hydraulic unit using a lever (carefully) and remove it. The location of the lever installation is indicated by the arrow.
VN 4.018
41. Disconnect the pressure pipe (11) from the hydraulic unit (drawing VN 4.019).
VN 4.019
42. Remove the hydraulic drive oil reservoir (drawing VN 4.020).
VN 4.020 Removing and installing the oil reservoir: 1. Oil reservoir; 2. Screw; 3. Oil supply pipe to the hydraulic pump; 4. Oil return pipe
43. Remove the ventilation tubes (6) and (7) (drawing VN 4.010).
44. Remove the ventilation pipe (15) and ventilation manifold (4).
45. Remove the reverse gear lock (3).
46. Remove the bracket (8).
47. Disconnect the wiring harness (19).
48. Remove the bracket (18).
49. Remove the clutch control mechanism (drawing VN 4.021).
VN 4.021 Removing and installing the clutch control mechanism:1. Retainer; 2. Control tube; 3. Clutch control mechanism position sensor connector; 4. Screws; 5. Clutch control mechanism
50. Remove the rear part of the gearbox housing (drawing VN 4.022)
VN 4.022 Removing the rear part of the gearbox housing: 1. Output shaft; 2.3. Special puller kit; 4. Universal puller; 5. Special grips
51. Remove the main shaft (1) of the gear shift mechanism (drawing VN 4.023).
52. Unscrew the 4 screws (2) securing the gear shift mechanism.
53. Install the mounting plate (7) on the primary (4) and intermediate (5) shafts
VN 4.023 Removing the main shaft of the gearshift mechanism: 1. Main shaft of the gear shift mechanism; 2. Screws; 3. Gear shift mechanism; 4. Primary shaft of the gearbox; 5. Intermediate shaft; 6. Main shaft; 7. Mounting plate
54. Remove the gear shift mechanism (3).
55. Remove the primary shaft (7), intermediate shaft (5) and main shaft (6) (drawing VN 4.024).
VN 4.024 Gearbox disassembly: 3. Gear shift mechanism; 5. Intermediate shaft; 6. Main shaft; 7. Primary shaft
Gearbox assembly
56. Install the main and intermediate shafts with the gear shift mechanism.
57. Install the rear part of the gearbox housing.
58. Install the bracket (18) (drawing VN 4.010).
59. Secure the wire harness (19).
60. Install the bracket (8).
61. Insert the reverse gear lock (3) into the hole until it stops.
VN 4.025 Checking the oil level in the gearbox: 1. Drain plug; 2. Oil filter plug; 3. Two-pin connector (X22/18)
62. Install ventilation pipes (15), (4), (6), (7).
63. Install the clutch release mechanism.
64. Install the oil reservoir.
65. Install the hydraulic unit.
66. Install the steering angle sensor mounting plate.
67. Install the steering angle sensors (drawing VN 4.014). To do this, insert the sensor (6), previously turned 90°, into place and fix it by turning it to the right. Insert the sensor (5), previously turned 45° to the right, into place and turn it to the left. Tighten the screw (3) located in the right rear corner of the steering angle sensor mounting plate.
68. Connect the connectors (1) of the sensors and attach them to the bracket (4) (drawing VN 4.014).
69. Install the hydraulic pump.
70. Install the speed sensor.
71. Replace the plug (1) (drawing VN 4.025) oil drain holes.
72. Unscrew the oil filter plug (2).
73. Fill with transmission oil. The oil level should be 10 mm below the edge of the oil filler hole.
74. Install the oil filter plug (2).
75. Install the oil receiver (pressure accumulator).
76. Install the centering pins.
77. Install the gearbox.