Mainshaft Disassemble

Tools Required

• J 21427-A  Speedometer Gear Puller Adapter. See Special Tools .
• J 22912-01  Split Plate Bearing Puller
• J 24420-C  Harmonic Balancer Puller

1. If 2WD vehicle, remove the mainshaft bearing retainer.
   Fig 1: Removing Mainshaft Bearing Retainer (2WD)

   Courtesy of GENERAL MOTORS CORP.
2. Remove the following components from the mainshaft assembly:
   • The 2 shift forks (1)
   • The reverse idler gear (2)
   • The countershaft rear bearing (4)
   • The countershaft (3)
   Fig 2: Removing Reverse Idler Gear, Countershaft, & Components

   Courtesy of GENERAL MOTORS CORP.
3. If 2WD vehicle, using the J 21427-A  (2) and the. See Special Tools .J 24420-C  (1), remove the speed sensor reluctor wheel from the rear of the mainshaft.
   Fig 3: Removing Speed Sensor Reluctor Wheel (2WD)

   Courtesy of GENERAL MOTORS CORP.

   Do not reuse the reluctor wheel after removal.

4. If 2WD vehicle, remove the mainshaft rear bearing retaining ring (1) and the mainshaft rear bearing (2).
   Fig 4: Removing Mainshaft Rear Bearing & Retaining Ring (2WD)

   Courtesy of GENERAL MOTORS CORP.
5. Remove the mainshaft assembly from the input shaft.
   Fig 5: Removing Mainshaft Assembly

   Courtesy of GENERAL MOTORS CORP.
IMPORTANT: Leave the synchronizer ring on the 3rd/4th synchronizer assembly to prevent the synchronizer detent balls from popping out.
6. Remove the 4th gear synchronizer blocking ring and put on the 4th gear synchronizer assembly.
7. Remove the mainshaft front bearing from the input shaft.
8. Remove the 3rd/4th gear synchronizer retaining ring.
   Fig 6: Removing 3rd/4th Gear Synchronizer Retaining Ring

   Courtesy of GENERAL MOTORS CORP.
9. Scribe an alignment mark on the synchronizer hub and the synchronizer sleeve in order to properly reassemble the synchronizer hub assembly.
   Fig 7: View Of Alignment Marks On Synchronizer Hub & Synchronizer Sleeve

   Courtesy of GENERAL MOTORS CORP.
IMPORTANT: When removing the synchronizer hubs use the J 22912-01  under the gear for that synchronizer and not the synchronizer sleeve. Do not separate the synchronizer hub from the synchronizer sleeves. Leave the synchronizer rings with the synchronize assembly to prevent the synchronizer detent balls from popping out.
Fig 8: Using Press To Remove 3rd/4th Gear Synchronizer Components
Courtesy of GENERAL MOTORS CORP.
10. Using a hydraulic press and the J 22912-01  remove the 3rd/4th speed gear synchronizer hub assembly, the third speed gear and the synchronizer rings.
11. Remove the synchronizer assembly from the third gear.
12. Remove the 3rd speed gear needle bearing assembly (1).
    Fig 9: Identifying 3rd Gear Needle Bearing, 3rd Gear & Synchronizer Ring

    Courtesy of GENERAL MOTORS CORP.
13. Remove the following components:
    1. The 2nd speed gear 2 piece thrust washer
    2. The retainer ring
    Fig 10: Removing 2nd Gear 2 Piece Thrust Washer And Retainer Ring

    Courtesy of GENERAL MOTORS CORP.
14. Remove the following components:
    1. The 2nd speed gear (1)
    2. The 2nd speed gear needle bearing assembly (2)
    Fig 11: Removing 2nd Gear And Bearing Assembly
    Courtesy of GENERAL MOTORS CORP.
15. Remove the following components for the 2nd gear synchronizer:
    1. The synchronizer cone
    2. The blocker ring
    3. The reaction cone
    Fig 12: Removing 2nd Gear Synchronizer Components

    Courtesy of GENERAL MOTORS CORP.
16. Remove the 1st/2nd gear synchronizer retaining ring from the mainshaft.
    Fig 13: Removing 1st/2nd Gear Synchronizer Retaining Ring

    Courtesy of GENERAL MOTORS CORP.
17. Remove the 2nd gear synchronizer interim ring.
18. Scribe an alignment mark on the synchronizer hub and the synchronizer sleeve in order to properly reassemble the synchronizer hub assembly.
IMPORTANT: When removing the synchronizer hubs use the J 22912-01  under the gear for that synchronizer and not the synchronizer sleeve. Do not separate the synchronizer hub from the synchronizer sleeves. Leave the synchronizer rings with the synchronize assembly to prevent the synchronizer detent balls from popping out.
Fig 14: Using Press To Remove 1st/2nd Gear Synchronizer Hub & 1st Gear
Courtesy of GENERAL MOTORS CORP.
19. Using a hydraulic press and the J 22912-01  remove the 1st/2nd speed gear synchronizer hub and the 1st speed gear.
20. Remove the following components:
    1. The synchronizer cone (5)
    2. The blocker ring (4)
    3. The reactor cone (3)
    4. The synchronizer interim ring (2)
    5. The 1st speed gear (1)
    Fig 15: Removing 1st Gear Components

    Courtesy of GENERAL MOTORS CORP.
21. Remove the 1st speed gear needle bearing assembly.
    Fig 16: Removing 1st Gear Needle Bearing Assembly

    Courtesy of GENERAL MOTORS CORP.
22. Turn the mainshaft over to work on the output end.
23. Remove the following components:
    1. The 5th speed gear (3)
    2. The 5th speed gear needle bearing assembly (1). The needle bearing is split in order to remove it over the collar.
    Fig 17: Removing 5th Speed Gear, Synchronizer Ring & Needle Bearing Assembly

    Courtesy of GENERAL MOTORS CORP.
24. Remove the retaining ring for the 5th/Reverse synchronizer hub from the mainshaft.
    Fig 18: Removing 5th/Reverse Synchronizer Hub Retaining Ring

    Courtesy of GENERAL MOTORS CORP.
25. Scribe an alignment mark on the synchronizer hub and the synchronizer sleeve in order to properly assemble the synchronizer hub assembly.
IMPORTANT: When removing the synchronizer hubs, use the J 22912-01  under the gear for that synchronizer, not the synchronizer sleeve. Do not separate the synchronizer hub from the synchronizer sleeves. Keep the synchronizer rings with the synchronizer assembly to prevent the synchronizer detent balls from popping out.
Fig 19: Using Press To Remove 5th/Reverse Speed Gear Synchronizer Assembly & Reverse Speed Gear
Courtesy of GENERAL MOTORS CORP.
26. Using a hydraulic press and the J 22912-01  , remove the 5th/Reverse speed gear synchronizer assembly (1) and the reverse speed gear (2).
27. Remove the reverse speed gear needle bearing assembly (1).
    Fig 20: Removing Reverse Gear & Needle Bearing Assembly

    Courtesy of GENERAL MOTORS CORP.
28. Remove the reverse speed gear drag seal.
    Fig 21: Removing Reverse Gear Drag Seal

    Courtesy of GENERAL MOTORS CORP.