Mainshaft Disassemble

Tools Required

• J 8433  Two Jaw Puller
• J 22912-01  Split-Plate Bearing Puller
• J 44725  Gear Pack Assembly Fixture. See Special Tools .
• J 44726  2/3 Jaw Puller. See Special Tools .
• J 44749  Split Plate Bearing/Gear Puller

IMPORTANT: The input shaft is not secured to the mainshaft assembly. In order to prevent the loss of synchronizer springs and pressure pieces, shift the 4th/5th synchronizer sleeve to 5th gear before removing from the J 44725  . See Special Tools . Moving the synchronizer in 5th gear will lock the input shaft with the mainshaft.
Fig 1: Shifting 4th/5th Synchronizer Hub Into 5th Gear
Courtesy of GENERAL MOTORS CORP.
1. Shift the 4th/5th synchronizer hub into 5th gear position.
2. While supporting the input shaft, remove the mainshaft assembly from the J 44725  . See Special Tools . Flip the mainshaft over, and install in the J 44725  with the output end down. See Special Tools .
3. Shift the 4th/5th synchronizer sleeve to the neutral position. Ensure the synchronizer sleeve is locked in the neutral position. Moving the sleeve too far or not enough may cause the sleeve to jump out of position, and the synchronizer springs and pressure pieces may be lost.
4. Remove the input shaft and set it to the side.
   Fig 2: Removing Input Shaft

   Courtesy of GENERAL MOTORS CORP.
5. Install the J 22912-01  (2) under the mainshaft front bearing. Ensure the J 22912-01  is not pressing against the bearing cage.
   Fig 3: Installing J 8433 & J 22912-01 Under Mainshaft Front Bearing

   Courtesy of GENERAL MOTORS CORP.
6. Install the J 8433  (1) to the J 22912-01  (2).
7. Remove the mainshaft front bearing.
8. Remove the retaining ring for the 4th/5th synchronizer hub and discard.
   Fig 4: Removing 4th/5th Synchronizer Hub Retaining Ring

   Courtesy of GENERAL MOTORS CORP.
IMPORTANT: When you service the synchronizers, retain them in the order that they are removed. Keep the synchronizer components together and mark to identify correct location.
Fig 5: Removing Synchronizer Components
Courtesy of GENERAL MOTORS CORP.
9. Remove the 5th gear synchronizer blocking ring. Mark the blocking ring for correct assembly.
10. Cover the synchronizer assembly with a shop towel in order to prevent the loss of springs and pressure pieces.
11. Slide the synchronizer sleeve from the synchronizer hub.
12. Remove the shop towel with the pressure pieces and springs.
13. Remove the 4th/5th synchronizer hub using the J 44726  (1) and the J 44749  (2). See Special Tools .
    Fig 6: Using J 44726 & J 44749 To Remove 4th/5th Synchronizer Hub

    Courtesy of GENERAL MOTORS CORP.
    • Place the J 44749  under the 4th gear.
    • Remove the 4th gear and 4th/5th synchronizer hub together.
14. Remove the 4th gear from the 4th/5th synchronizer hub.
15. Remove the 4th gear synchronizer blocking ring. Mark the blocking ring for correct assembly.
16. Remove the 4th gear bearing.
    Fig 7: Removing 4th Gear Bearing

    Courtesy of GENERAL MOTORS CORP.
IMPORTANT: The 3rd gear and 4th gear bearings and bushings are identical parts. Mark or tag the parts for proper installation. If using the parts again, install in the same location as they were removed.
17. Tag the bearing for correct identification.
18. Use a hydraulic press to remove the 4th gear bushing, 3rd gear bushing, and 2nd/3rd synchronizer hub and related parts listed in the next step. Install the press plates under the 2nd gear.
    Fig 8: Using Press To Removing Mainshaft Components

    Courtesy of GENERAL MOTORS CORP.

    Depending on the press set up, the pressing action may have to be stopped to remove the individual parts before pressing off the next part. If available, a pressing bar about 25 cm (10 in) long can be used on the end of the mainshaft to press off the parts with one pressing action. Hold the mainshaft from dropping when the 3rd gear bushing is coming off the mainshaft.

IMPORTANT: The 3rd gear and 4th gear bearings and bushings are identical parts. Mark or tag the parts for proper installation. If using the parts again, install in the same location as they were removed.
Fig 9: Identifying Mainshaft Components
Courtesy of GENERAL MOTORS CORP.
19. Remove the following components from the mainshaft:
    1. The 4th gear bushing (1)
    2. The thrust washer (2)
    3. The 3rd gear (3)
    4. The 3rd gear bearing (4)
    5. The 3rd gear bushing (5)
    6. The 2nd/3rd synchronizer assembly (6)
    7. The 2nd gear (7)
    8. The 2nd gear bearing (8)
IMPORTANT: When you service the synchronizers, retain them in the same order as they were removed. Keep the synchronizer components together and mark to identify correct location.
Fig 10: Exploded View Of 2nd/3rd Synchronizer Assembly
Courtesy of GENERAL MOTORS CORP.
20. If necessary, disassemble the 2nd/3rd synchronizer assembly.
    1. Mark the location of the components for proper location during inspection and assembly.
    2. Remove the 3rd gear synchronizer inner ring (1).
    3. Remove the 3rd gear synchronizer middle ring (2).
    4. Remove the 3rd gear synchronizer blocking ring (3).
    5. Cover the synchronizer assembly with a shop towel when removing the sleeve to prevent loss of the balls, springs and pressure pieces.
    6. Remove the 2nd/3rd gear synchronizer sleeve (8) from the synchronizer hub (4).
    7. Remove the 2nd/3rd gear synchronizer detent balls (7), pressure pieces (6), and springs (5).
    8. Remove the 2nd gear synchronizer blocking ring (9).
    9. Remove the 2nd gear synchronizer middle ring (10).
    10. Remove the 2nd gear synchronizer inner ring (11).
IMPORTANT:
• Only remove the bearings if replacing the bearings. Do not use the bearings again after removal.
• You must also replace the race for the bearing being replaced.
21. Inspect the mainshaft center bearing. Refer to Bearings and Spacers Cleaning and Inspection .
22. Using a hydraulic press and the J 44749  (1), remove the mainshaft intermediate case bearing if necessary.
    Fig 11: Using J 44749 To Remove Intermediate Case Bearing

    Courtesy of GENERAL MOTORS CORP.