Mainshaft Disassemble

Tools Required

• J 22912-01  Split Plate Bearing Puller
• J 36513  Gear and Bearing Separator Plate
• J 44707  T-Bar Push Puller
• J 44749  Split Plate Bearing Gear Puller. See Special Tools .
• J 44759  Adapter 3/8 NC to 5/8 NF

IMPORTANT: For installation alignment scribe an alignment mark on the synchronizer hubs and synchronizer sleeves before removing. To prevent the synchronizer springs and struts from being lost, do not separate the synchronizer hubs from the synchronizer sleeves. Keep the synchronizer clutch gear and the blocking rings with the synchronizer hubs. Organize the components in order to install the components in their original location and position.
1. Position the mainshaft assembly in a soft jaw vise for ease of disassembly.
2. Remove the 4th speed gear clutch gear.
   Fig 1: Removing 4th Gear Clutch Gear & Synchronizer Ring

   Courtesy of GENERAL MOTORS CORP.
3. Remove the 4th speed gear synchronizer ring.
4. Remove the main drive gear thrust bearing.
   Fig 2: Removing Main Drive Gear Thrust Bearing

   Courtesy of GENERAL MOTORS CORP.
5. Using the J 44707  (1), the J 44759  (2), and the J 36513  (3), remove the 3rd/4th synchronizer hub from the mainshaft with the 3rd speed gear.
   Fig 3: Removing 3rd/4th Synchronizer Hub

   Courtesy of GENERAL MOTORS CORP.
   • Position the J 36513  (3) behind 3rd gear.
   • A hydraulic press with a large bearing splitter can also be used.
6. Remove the 3rd speed gear bearing.
   Fig 4: Removing 3rd Gear Bearing & Mainshaft Bearing Spacer

   Courtesy of GENERAL MOTORS CORP.
7. Remove the mainshaft bearing spacer.
IMPORTANT: The wear of the 1st and 2nd speed synchronizer can only be measured correctly while the synchronizer and the speed gears are installed on the mainshaft. The synchronizer uses a fixed inner cone.
8. In order to measure the wear gap for the 1st speed gear position, perform the following:
   1. Engage the 1st/2nd synchronizer sleeve in the 2nd speed gear position.
   2. Move the sleeve, with light, even, pressure towards 1st gear. The inserts will press against the blocker ring.
   3. Insert the feeler gage between the synchronizer hub and the blocker ring to measure the wear gap.

      The 1st speed synchronizer wear gap is 1.37-0.31 mm (0.054-0.012 in).

   Fig 5: Measuring Wear Gap For 1st Speed Gear Position
   Courtesy of GENERAL MOTORS CORP.
9. In order to measure the wear gap for the 2nd gear position, perform the following:
   1. Engage the 1st/2nd synchronizer sleeve in the 1st speed gear position.
   2. Move the sleeve, with light, even, pressure towards 2nd gear. The inserts will press against the blocker ring.
   3. Insert the feeler gage between the 2nd gear clutch teeth and the blocker ring to measure the wear gap.

      The 2nd speed synchronizer wear gap is 2.16-1.14 mm (0.085-0.045 in).

   Fig 6: Measuring Wear Gap For 2nd Speed Gear Position
   Courtesy of GENERAL MOTORS CORP.
10. Remove the 2nd speed gear thrust washer retainer ring.
    Fig 7: Removing 2nd Speed Gear Thrust Washer Retaining Ring & Pin

    Courtesy of GENERAL MOTORS CORP.
11. Remove the 2nd speed gear thrust washer.
12. Remove the 2nd speed gear thrust washer retaining pin.
13. Remove the 2nd speed gear.
    Fig 8: Removing 2nd Speed Gear

    Courtesy of GENERAL MOTORS CORP.
14. Remove the 2nd speed gear bearing.
    Fig 9: Removing 2nd Speed Gear Bearing

    Courtesy of GENERAL MOTORS CORP.
IMPORTANT: For installation alignment scribe an alignment mark on the synchronizer hubs and synchronizer sleeves before removing. To prevent the synchronizer springs and struts from being lost, do not separate the synchronizer hubs from the synchronizer sleeves. Keep the synchronizer clutch gear and the blocking rings with the synchronizer hubs. Organize the components in order to install the components in their original location and position.
15. Remove the following 1st/2nd gear synchronizer components:
    1. The 2nd speed gear synchronizer outer ring retaining ring front (1)
    2. The 2nd speed gear synchronizer inner ring (2)
    3. The 2nd speed gear synchronizer center ring (4)
    4. The 2nd speed gear synchronizer outer ring (5)
    5. The 2nd speed gear synchronizer outer ring retaining ring rear (3)
    6. The 1st/2nd speed synchronizer assembly (6)
    7. The 1st speed gear synchronizer outer ring (7)
    8. The 1st speed gear synchronizer center ring (8)
    9. The 1st speed gear outer ring retaining ring front (9)
    10. The 1st speed gear synchronizer inner ring (10)
    11. The 1st speed gear synchronizer outer ring retaining ring rear (11)
    Fig 10: Identifying 1st/2nd Gear Synchronizer Components
    Courtesy of GENERAL MOTORS CORP.
16. Using a hydraulic press and the J 44749  or equivalent, remove the rear mainshaft bearing. See Special Tools . Use the J 44749  under the reverse gear. See Special Tools .
    Fig 11: Using Press To Remove Rear Mainshaft Bearing

    Courtesy of GENERAL MOTORS CORP.
17. Remove the rear mainshaft bearing.
    Fig 12: Removing Rear Mainshaft Bearing & Reverse Gear

    Courtesy of GENERAL MOTORS CORP.
18. Remove the reverse gear thrust washer.
19. Remove the reverse gear.
20. Remove the reverse gear bearing.
    Fig 13: Removing Reverse Gear Bearing & Mainshaft Gear Spacer

    Courtesy of GENERAL MOTORS CORP.
21. Remove the mainshaft gear spacer.
22. Remove the retainer ring for the reverse gear clutch hub.
23. Remove the reverse gear clutch hub and the synchronizer ring.
    Fig 14: Removing Reverse Gear Clutch Hub & Synchronizer Ring

    Courtesy of GENERAL MOTORS CORP.
24. Remove the 1st speed gear.
    Fig 15: Removing 1st Speed Gear & Bearing

    Courtesy of GENERAL MOTORS CORP.
25. Remove the 1st speed gear bearing.