GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Transmission/Transaxle 🢒 Manual Transmission - ZF S6-650 🢒 Transmission Assemble

Tools Required

    • J 8092 Universal Driver
    • J 8614-01 Flange and Pulley Holding Tool
    • J 21465-13 Drive Handle Extension
    • J 25070 Heat Gun - 500-750 F
    • J 26900-12 Dial Indicator
    • J 29763 Static Timing Gage
    • J 36850 Transjel Lubricant
    • J 44725 Gear Pack Assembly Fixture
    • J 44728 Bearing Race Remover
    • J 44731 Input Shaft Seal Installer
    • J 44732 Output Shaft Seal Installer
    • J 44733 Bearing Race Remover
    • J 44735 Installation Tube
    • J 44736 Bridge and Forcing Screw
    • J 44739 Dial Indicator Bracket
    • J 44745 Countershaft Bearing Race Installer
    • J 44746 Mainshaft/Input Shaft Bearing Race Installer

    Object Number: 662020 Size: SH

    Notice: Various transmission components require heating to 150°C (300°F) for 30 minutes for proper installation. Overheating may damage the components. Under-heating the components may cause hard installation, which may damage the components.

    Important: 

       • Certain transmission components require preheating to 150°C (300°F). In order to preheat the components, use an electric oven. It is recommended to purchase a roaster/oven style locally. The oven should have a temperature setting thermostat.
       • Lubricate all bearings, shafts, and synchronizers with transmission fluid GM P/N 12378515 (Canadian P/N 88900701) during installation.

  1. Preheat the following components for 30 minutes to 150°C (300°F) in an electric oven:
    2. • The 6th gear bearing bushing
    • The reverse gear bearing bushing
    • The reverse gear thrust washer
    • The mainshaft rear bearing
  2. Turn the mainshaft assembly over 180 degrees so that the input shaft is on the J 44725 . Hold the input shaft to the mainshaft while turning over.
  3. Position the countershaft on the J 44725 .

    4. Roll the countershaft into place to merger the countershaft and mainshaft gears.


    Object Number: 724133 Size: SH
  4. Install the spacer for the 6th speed gear synchronizer hub on the countershaft.

    5. Object Number: 663680 Size: SH
  5. Assemble the 2nd/3rd shift fork and shift shaft and the 4th/5th shift fork and shift shaft in the interlock plate.
    6. • The part number end of the shift shafts goes up.
    • The part number side of the interlock plate goes down.
  6. Install the 2nd/3rd shift fork and the 4th/5th shift fork in the synchronizer sleeves.

    7. Object Number: 662019 Size: SH
  7. Install the intermediate case over the countershaft, the mainshaft, 2nd/3rd shift shaft, and the 4th/5th shift shaft.
    8. • Align the shift shafts straight with the shift shaft bearings.
    • Wiggle the intermediate case over the shift shafts while installing.

    Object Number: 663713 Size: SH
  8. Install the shift interlock plate to the intermediate case. The part number side faces away from the intermediate case.

    9. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  9. Install the interlock plate bolts. Ensure the shoulder of the bolts do not catch on the plate.

    10. Tighten
    Tighten the interlock plate bolts to 10 N·m (88 lb in).

  10. Ensure the interlock plate moves freely.

    11. Object Number: 724135 Size: SH
  11. Install the retaining ring in the 6th speed gear synchronizer hub, if removed.
  12. Install the 6th speed gear synchronizer hub on the countershaft.
    13. • The hub side with the retaining ring goes toward the intermediate case.
    • The hub should slide on the countershaft.

    Object Number: 740023 Size: SH
  13. If not already assembled, assemble the 6th gear synchronizer assembly.

    14. The 6th gear synchronizer springs are 22.7 mm (0.893 in) long.

    13.1. Install all three springs and the pressure pieces in the synchronizer sleeve.
    13.2. Install the 6th gear synchronizer sleeve on the hub. The part numbered side goes up.

            Important: In order to prevent the springs and pressure pieces from jumping out of position, install the 6th gear synchronizer blocking ring. Move the sleeve to lock the pressure pieces in position.

    13.3. Install the 6th gear synchronizer blocking ring. Align the tabs on the blocking ring with the slots in the hub.
    13.4. Pull up on the sleeve to lock the pressure pieces in the neutral position.

    Caution: Refer to Handling Preheated Parts Caution in the Preface section.


    Object Number: 724142 Size: SH
  14. Wearing protective gloves, install the preheated 6th gear bushing on the countershaft. Rotate the bushing while installing in order to seat them fully and squarely.

    15. Object Number: 662009 Size: SH
  15. Install the 6th speed gear bearing (3).
  16. Install the 6th speed gear (2).
  17. Install the 6th speed gear spacer washer (1).
  18. Lightly lubricate the components with GM P/N 12378515 (Canadian P/N 88900701).

    19. Object Number: 662008 Size: SH
  19. Install the 6th speed gear retaining ring.
    20. • The retaining rings are different thicknesses.
    • Select a retaining ring that fills the groove.
    • Retaining ring tabs should be under the gear teeth.
    • Ensure the retaining ring is fully seated.

    Object Number: 724270 Size: SH
  20. If the 1st/reverse synchronizer requires assembly, use the following procedure:
    21. 20.1. Lightly lubricate the components with GM P/N 12378515 (Canadian P/N 88900701).
    20.2. With the oil grooves, or the part number side up, install the synchronizer hub on the 1st gear synchronizer blocking ring.
    20.3. With the synchronizer sleeve chamfer side down, install the sleeve on the hub.
    20.4. Install the synchronizer springs and pressure pieces.
    20.5. Install the reverse gear synchronizer blocking ring.

    Object Number: 724148 Size: SH
  21. Install the following components on the mainshaft:
    22. 21.1. Lightly lubricate the bearings with GM P/N 12378515 (Canadian P/N 88900701).
    21.2. The 1st gear bearings
    21.3. The 1st speed gear
    21.4. The 1st/reverse gear synchronizer assembly with the hub part numbers facing up

    Caution: Refer to Handling Preheated Parts Caution in the Preface section.


    Object Number: 724149 Size: SH
  22. Wearing protective gloves, install the preheated reverse speed gear bushing on the mainshaft. Rotate the bushing while installing to ensure the bushing is fully and squarely seated.

    23. Object Number: 724150 Size: SH
  23. Install the reverse gear bearings.
  24. Lightly lubricate the bearings with GM P/N 12378515 (Canadian P/N 88900701).
  25. Install the reverse gear.

    26. Caution: Refer to Handling Preheated Parts Caution in the Preface section.


    Object Number: 742362 Size: SH
  26. If RWD, wearing protective gloves, install the preheated thrust washer on the mainshaft.
  27. Use the J 44735 and a hammer to ensure the thrust washer is fully and squarely seated.

    28. Caution: Refer to Handling Preheated Parts Caution in the Preface section.


    Object Number: 724159 Size: SH

    Important: The mainshaft rear bearing for a 4WD vehicle is a sealed bearing.

  28. Wearing protective gloves, install the preheated mainshaft rear bearing on the mainshaft. Rotate the bearing while installing to ensure the bearing is fully and squarely seated.

    29. Object Number: 722214 Size: SH
  29. If 4WD, install the retaining ring for the mainshaft rear bearing. Ensure the retaining ring is fully seated.

    30. Object Number: 724163 Size: SH
  30. If RWD, install the vehicle speed sensor reluctor wheel.

    31. The reluctor wheel should slide on the mainshaft.


    Object Number: 662003 Size: SH
  31. Install the 6th gear shift fork and rail.
    32. 31.1. The part numbered end goes up on the shift rail.
    31.2. Install the shift fork to the 6th gear synchronizer assembly.
    31.3. Move the shift interlock plate toward the 1st/reverse position if necessary.
    31.4. Tap the shift rail with a soft-face hammer into the shift fork and the intermediate case.

    Object Number: 662004 Size: SH
  32. Install the 1st/reverse shift fork and rail.
    33. 32.1. The part numbered end goes up on the shift rail.
    32.2. Install the shift fork to the 1st/reverse gear synchronizer hub.
    32.3. Move the interlock plate toward 6th gear shift rail.
    32.4. Tap the shift rail with a soft-face hammer into the shift fork and the intermediate case.

    Object Number: 663682 Size: SH
  33. Install the NEW roll pins in the 6th gear shift fork (2). A roll pin goes in each hole.
  34. Install the NEW roll pins in the 1st/reverse gear shift fork (1). A roll pin goes in each hole.

    35. Object Number: 724351 Size: SH
  35. If removed, install the shift block on the main shift rail.
    36. 35.1. The part numbers on the shift block and the part number on the shift rail face the same direction.
    35.2. Install the NEW large diameter roll pin.
    35.3. Install the NEW small diameter roll pin with the roll pin split 180 degrees from the large roll pin split.

    Object Number: 662001 Size: SH
  36. Install the front internal shift lever on the main shift rail.
    37. • Align the roll pin, or lever end, toward the part numbered end of the shift rail.
    • Do not install the roll pins.
  37. With the part numbered end pointing up, install the main shift rail.

    38. Object Number: 724177 Size: SH
  38. Align the shift block teeth on the main shift rail with the shift interlock plate.

    39. The center tooth on the shift block installs between the two teeth on the shift interlock plate.

  39. Position the front internal shift lever to align with the notch in the 2nd/3rd shift rail.

    40. Object Number: 661262 Size: SH
  40. Install the NEW roll pins in the internal shift control front lever.
    41. 40.1. Install the large diameter roll pin.
    40.2. Align the split on the roll pin away from the transmission.
    40.3. Install the small diameter roll pin inside of the large diameter roll pin.
    40.4. Align the split on the roll pin toward the transmission.

    Object Number: 661975 Size: SH
  41. Install the internal shift control rear lever on the main shift rail.

    42. Object Number: 661258 Size: SH
  42. Align the levers on the internal shift control rear lever with the slots in the 1st/reverse gear shift rail and the 6th gear shift rail.
  43. Install the NEW roll pins in the internal shift control rear lever.
    44. 43.1. Install the large diameter roll pin.
    43.2. Align the split on the roll pin away from the transmission.
    43.3. Install the small diameter roll pin inside of the large diameter roll pin.
    43.4. Align the split on the roll pin toward the transmission.

    Object Number: 661996 Size: SH
  44. Install the shift shaft detent plungers and springs.
  45. Apply a thin layer of gasket maker GM P/N 12378517 (Canadian P/N 88900757) to the shift shaft detent caps.
  46. Using an 11 mm (27/64 in) punch, install the shift shaft detent caps.

    47. Object Number: 662022 Size: SH
  47. Shift the transmission into 5th gear in order to lock the input shaft to the mainshaft.

    48. Object Number: 661238 Size: SH
  48. Install S-hooks and a chain to the intermediate case.

    49. Object Number: 661239 Size: SH
  49. Position the front of the front case on boards in order to allow the protrusion of the input shaft.
  50. Using a suitable lifting device, install the gear assembly to the front case.
    51. • Lower the gear assembly slowly in order to align the intermediate case dowel pins with the front case.
    • Do not use a sealer at this time.

    Object Number: 661237 Size: SH

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  51. Install the two intermediate to front case bolts.

    52. Tighten
    Tighten the intermediate case bolts to 23 N·m (17 lb ft).


    Object Number: 821070 Size: SH
  52. Assemble the J 44739 to the intermediate case, to measure the countershaft preload.
    53. 52.1. Install the crosspiece so that the 2 holes are closer to the single bolt hole upright in the lowest notch. Do not tighten the thumbscrew.
    52.2. Install the crosspiece to the 2 bolt hole upright in the lowest notch. Do not tighten the thumbscrew.
    52.3. Using a case bolt, install the single bolt hole upright to the 7th case bolt hole from the top, on the right side of the case.
    52.4. Using a case bolt in the hole away from the upright, install the 2 bolt hole upright to the 5th case bolt hole from the top, on the left side of the case.
    52.5. Tighten the crosspiece thumbscrews.

    Object Number: 724197 Size: SH
  53. Use the following procedure in order to measure the countershaft bearing clearance:
    54. 53.1. Install the J 26900-12 or the J 29763 in the J 44739 .
    53.2. Adjust the J 26900-12 or the J 29763 to zero.
    53.3. Using a suitable prying tool, lift up the countershaft.
    53.4. Record the dial indicator reading. This is the countershaft bearing clearance.
  54. Using the following formula, establish the shim thickness required for the countershaft bearing preload:
    55. 54.1. Add the mainshaft preload specification 0.02-0.09 mm (0.0008-0.0035 in) to the countershaft bearing clearance measurement.
    54.2. The total is the shim thickness required under the countershaft bearing race in order to set the bearing preload.

    Example

       • 1.8 mm (0.070 in) mainshaft bearing clearance measurement
       • Plus 0.02-0.09 mm (0.0008-0.0035 in) countershaft preload specification
       • Equals 1.82-1.89 mm (0.070-0.074 in) shim thickness required

    Object Number: 821071 Size: SH
  55. Assemble the J 44739 to the intermediate case, to measure the mainshaft preload.
    56. 55.1. Install the crosspiece so that the 2 holes are closer to the single bolt hole upright in the upper notch, for RWD, or center notch for 4WD. Do not tighten the thumbscrew.
    55.2. Install the crosspiece to the 2 bolt hole upright in the upper notch, for RWD, or center notch for 4WD. Do not tighten the thumbscrew.
    55.3. Using a case bolt, install the single bolt hole upright to the 3rd case bolt hole from the top, on the right side of the case.
    55.4. Using a case bolt in the hole closest to the upright, install the upright with the 2 bolt holes to the 6th case bolt hole from the top, on the left side of the case.
    55.5. Tighten the thumbscrews.

    Object Number: 724199 Size: SH
  56. Use the following procedure in order to measure the mainshaft bearing clearance.
    57. 56.1. Install the J 26900-12 or the J 29763 in the J 44739 .
    56.2. Adjust the J 26900-12 or the J 29763 to zero.
    56.3. Using a suitable prying tool, lift the mainshaft up.
    56.4. Record the dial indicator reading. This is the mainshaft bearing clearance measurement.
  57. Using the following formula, establish the shim thickness required for the mainshaft bearing preload:
    58. 57.1. Measure the input shaft bearing oil deflector thickness. Record this measurement.
    57.2. Subtract the oil deflector measurement from the mainshaft bearing clearance measurement.
    57.3. Add the mainshaft preload specification 0.02-0.09 mm (0.0008-0.0035 in).
    57.4. The total is the shim thickness required under the input bearing race in order to set the bearing preload.

    Example

       • 0.50 mm (0.020 in) oil deflector thickness
       • minus 2.2 mm (0.087 in) mainshaft bearing clearance measurement
       • equals 1.7 mm (0.067 in)
       • plus 0.02-0.09 mm (0.008-0.0035 in) mainshaft preload specification
       • equals 1.75 mm (0.069 in) shim thickness required

    Object Number: 661237 Size: SH
  58. Remove the 2 bolts retaining the intermediate case to the front case.

    59. Object Number: 661239 Size: SH
  59. Using S-hooks, a chain and a suitable lifting device, remove the gear assembly.

    60. Object Number: 722220 Size: SH
  60. Remove the mainshaft front bearing race using the J 44736  (1) and the J 44733  (2).
    61. 60.1. Expand the J 44733  (2) to fit securely under the bearing race.
    60.2. Align the legs of the J 44733 to rest on the webbing of the case.
    60.3. Remove the mainshaft front bearing race.

    Object Number: 722224 Size: SH
  61. Remove the countershaft front bearing race using the J 44736  (1) and the J 44728  (2).
    62. 61.1. Install the J 44728  (2) in order for the fingers to fit in the notches in the case.
    61.2. Expand the J 44728  (2) to fit securely in the bearing race.
    61.3. Align the legs of the J 44736 to rest on the webbing of the case.
    61.4. Remove the countershaft front bearing race.

    Object Number: 722853 Size: SH
  62. Using the J 25070 , heat the front case for 10-15 minutes.

    63. Object Number: 724204 Size: SH
  63. Install the required shims for the countershaft bearing preload.

    64. Object Number: 722852 Size: SH

    Important: Install the bearing races with the front case still hot. Do not allow the front case to cool.

  64. Install the countershaft front bearing race using the J 8092  (1), J 21465-13  (2) and the J 44745  (3).

    65. Object Number: 722690 Size: SH
  65. Install the oil trough.

    66. Object Number: 722688 Size: SH
  66. Install the required shims for the mainshaft bearing preload.
  67. Install the input shaft gear oil deflector.

    68. Object Number: 722851 Size: SH
  68. Install the mainshaft front bearing race using the J 8092  (1),J 21465-13  (2) and theJ 44746  (3).
  69. Allow the front case to cool.

    70. Object Number: 661239 Size: SH
  70. Apply a thin layer of gasket maker GM P/N 12378517 (Canadian P/N 88900757) to the sealing surface of the front case.
  71. Using a suitable lifting device, install the gear assembly to the front case.

    72. Object Number: 661237 Size: SH
  72. Install the 2 intermediate case to front case bolts.

    73. Tighten
    Tighten the intermediate case bolts to 23 N·m (17 lb ft).


    Object Number: 661233 Size: SH
  73. Apply a thin layer of gasket maker GM P/N 12378517 (Canadian P/N 88900757) to the sealing surface of the rear case.
  74. Install the rear case on the intermediate case.
  75. Using a soft-face hammer, tap down on the rear case to seat it on the dowel pins. Do not use the bolts to draw the case together.
  76. Install the required brackets and the rear case bolts.

    77. Tighten
    Tighten the rear case bolts in a crossover sequence to 23 N·m (17 lb ft).


    Object Number: 661234 Size: SH
  77. Apply a thin layer of threadlocker GM P/N 12345382 (Canadian P/N 10953489) to the threads of the shift shaft detent sleeve.
  78. Install the shift shaft detent plunger and sleeve.

    79. Tighten
    Tighten the detent sleeve to 65 N·m (48 lb ft).


    Object Number: 663712 Size: SH
  79. If RWD, install the vehicle speed sensor (VSS), with an O-ring seal, in the rear case.
  80. Install the VSS bolt.

    81. Tighten
    Tighten the VSS bolt to 20 N·m (15 lb ft).


    Object Number: 724209 Size: SH
  81. If RWD, install the rear oil seal using the J 44732 . The seal installer will install the seal at the correct depth.
  82. Lightly lubricate the seal surface with J 36850 or equivalent.

    83. Object Number: 661231 Size: SH
  83. If RWD, install the propeller shaft yoke.
  84. Install a NEW propeller shaft yoke nut.

    85. Object Number: 727452 Size: SH
  85. Install the J 8614-01 in order to hold the transmission shaft from rotating.

    86. Tighten
    Tighten the NEW propeller shaft yoke nut to 330 N·m (244 lb ft).


    Object Number: 661219 Size: SH
  86. Install the transmission drain plug and O-ring seal. Ensure the O-ring seal is not damaged.

    87. Tighten
    Tighten the drain plug to 35 N·m (26 lb ft).


    Object Number: 661223 Size: SH
  87. If the lower shift lever requires installation before installing in the vehicle, apply a thin layer of gasket maker GM P/N 12378517 (Canadian P/N 88900757) to the sealing surface of the lower shift control lever.
  88. Install the lower shift control lever.
  89. Install the lower shift control lever bolts.

    90. Tighten
    Tighten the lower shift control lever bolts to 23 N·m (17 lb ft).


    Object Number: 724213 Size: SH
  90. Position the transmission on the transmission bottom.
  91. Install the input shaft seal using the J 44731 .
  92. Shift the transmission through all of the gears to ensure proper shifting.
  93. Rotate the transmission by the input shaft.

    94. There should be resistance to turn.

Tools Required

    • J 8092 Universal Driver Handle - 3/4 in - 10
    • J 8614-01 Flange and Pulley Holding Tool
    • J 21465-13 Driver Handle Extension
    • J 22828 Input and Countershaft Race Installer
    • J 25070 Heat Gun
    • J 26900-12 Dial Indicator - 1-10 mm
    • J 29763 Dial Indicator
    • J 36850 Transjel Lubricant
    • J 44725 Gear Pack Assembly Fixture
    • J 44728 Bearing Race Remover
    • J 44732 Output Shaft Seal Installer
    • J 44733 Bearing Race Remover
    • J 44735 Installation Tube
    • J 44736 Bridge and Forcing Screw
    • J 44739 Dial Indicator Bracket
    • J 44745 Countershaft Bearing Race Installer
    • J 44746 Mainshaft/Input Shaft Bearing Race Installer
    • J 45277 Input Shaft Seal Installer
    • J 45279 Assembly Stand

    Notice: Refer to Heating Transmission Component Notice in the Preface section.


    Object Number: 662020 Size: SH

    Important: 

       • Certain transmission components require preheating to 150°C (300°F). In order to preheat the components use an electric oven. A roaster/oven style is recommended. The oven should have a temperature setting thermostat.
       • Lubricate all of the bearings, shafts, and synchronizers with transmission fluid GM P/N United States 12378515, GM P/N Canada 88900701, during installation.

  1. Preheat the following components to 150°C (300°F), for 30 minutes, in an electric oven:
    2. • The 6th gear bearing bushing
    • The reverse gear bearing bushing
    • The reverse gear thrust washer
    • The mainshaft rear bearing
  2. Turn the mainshaft assembly over 180 degrees, so that the input shaft is on the J 44725 . Hold the input shaft to the mainshaft while turning over.
  3. Position the countershaft on the J 44725 .

    4. Roll the countershaft into place to merger the countershaft and mainshaft gears.


    Object Number: 724133 Size: SH
  4. Install the spacer for the 6th speed gear synchronizer hub on the countershaft.

    5. Object Number: 663680 Size: SH
  5. Assemble the 2nd/3rd shift fork and shift shaft and the 4th/5th shift fork and shift shaft in the interlock plate.
    6. • The part number end of the shift shafts go up.
    • The part number side of the interlock plate goes down.
  6. Install the 2nd/3rd shift fork and the 4th/5th shift fork in the synchronizer sleeves.

    7. Object Number: 662019 Size: SH
  7. Install the intermediate case over the countershaft, the mainshaft, 2nd/3rd shift shaft, and the 4th/5th shift shaft.
    8. • Align the shift shafts straight with the shift shaft bearings.
    • Wiggle the intermediate case over the shift shafts while installing.

    Object Number: 663713 Size: SH
  8. Install the shift interlock plate to the intermediate case. The part number side faces away from the intermediate case.

    9. Notice: Refer to Fastener Notice in the Preface section.

  9. Install the interlock plate bolts. Ensure the shoulder of the bolts do not catch on the plate.

    10. Tighten
    Tighten the interlock plate bolts to 10 N·m (88 lb in).

  10. Ensure the interlock plate moves freely.

    11. Object Number: 724135 Size: SH
  11. Install the retaining ring in the 6th speed gear synchronizer hub, if removed.
  12. Install the 6th speed gear synchronizer hub on the countershaft.
    13. • The hub side with the retaining ring goes toward the intermediate case.
    • The hub should slide on the countershaft.

    Object Number: 740023 Size: SH
  13. If not already assembled, assemble the 6th gear synchronizer assembly.

    14. The 6th gear synchronizer springs are 22.7 mm (0.893 in) long.

    13.1. Install all 3 springs and the pressure pieces in the synchronizer sleeve.
    13.2. Install the 6th gear synchronizer sleeve on the hub. The part numbered side goes up.

            Important: In order to prevent the springs and pressure pieces from coming out of position, install the 6th gear synchronizer blocking ring. Then move the sleeve to lock the pressure pieces in position.

    13.3. Install the 6th gear synchronizer blocking ring. Align the tabs on the blocking ring with the slots in the hub.
    13.4. Pull up on the sleeve to lock the pressure pieces in the neutral position.

    Caution: Refer to Handling Preheated Parts Caution in the Preface section.


    Object Number: 724142 Size: SH
  14. Wear protective gloves to install the preheated 6th gear bushing on the countershaft. In order to fully and squarely seat the bushing, rotate the bushing while installing it.

    15. Object Number: 662009 Size: SH
  15. Install the 6th speed gear bearing (3).
  16. Install the 6th speed gear (2).
  17. Install the 6th speed gear spacer washer (1).
  18. Lightly lubricate the components with GM P/N United States 12378515, GM P/N Canada 88900701.

    19. Object Number: 662008 Size: SH
  19. Install the retaining ring for the 6th speed gear.
    20. • The retaining rings are different thicknesses.
    • Select a retaining ring that fills the groove.
    • Retaining ring tabs should be under the gear teeth.
    • Ensure the retaining ring is fully seated.

    Object Number: 724270 Size: SH
  20. If the 1st/reverse synchronizer requires assembly, use the following procedure:
    21. 20.1. Lightly lubricate the components with GM P/N United States 12378515, GM P/N Canada 88900701.
    20.2. With the oil grooves or the part number side up, install the synchronizer hub on the 1st gear synchronizer blocking ring.
    20.3. With the synchronizer sleeve chamfer side down, install the sleeve on the hub.
    20.4. Install the synchronizer springs and pressure pieces.
    20.5. Install the reverse gear synchronizer blocking ring.

    Object Number: 724148 Size: SH
  21. Install the following components on the mainshaft:
    22. 21.1. Lightly lubricate the bearings with GM P/N United States 12378515, GM P/N Canada 88900701.
    21.2. The 1st gear bearings
    21.3. The 1st speed gear
    21.4. The 1st/reverse gear synchronizer assembly with the hub part numbers facing up

    Caution: Refer to Handling Preheated Parts Caution in the Preface section.


    Object Number: 724149 Size: SH
  22. Wear protective gloves to install the preheated reverse speed gear bushing on to the mainshaft. Rotate the bushing while installing it to ensure the bushing is fully and squarely seated.

    23. Object Number: 724150 Size: SH
  23. Install the reverse gear bearings.
  24. Lightly lubricate the bearings with GM P/N United States 12378515, GM P/N Canada 88900701.
  25. Install the reverse gear.

    26. Caution: Refer to Handling Preheated Parts Caution in the Preface section.


    Object Number: 742362 Size: SH
  26. If RWD, wear protective gloves to install the preheated thrust washer on to the mainshaft.
  27. Use the J 44735 and a hammer to ensure the thrust washer is fully and squarely seated.

    28. Caution: Refer to Handling Preheated Parts Caution in the Preface section.


    Object Number: 724159 Size: SH
  28. Wear protective gloves to install the preheated mainshaft rear bearing on to the mainshaft. Rotate the bearing while installing it, to ensure the bearing is fully and squarely seated.

    29. Object Number: 811513 Size: SH
  29. Install the vehicle speed sensor reluctor wheel.

    30. The reluctor wheel should slide on the mainshaft.


    Object Number: 811471 Size: SH
  30. Install the 6th gear shift fork and rail.
    31. 30.1. The part numbered end goes up on the shift rail.
    30.2. Install the shift fork to the 6th gear synchronizer assembly.
    30.3. Move the shift interlock plate toward the 1st/reverse position, if necessary.
    30.4. Using a soft-face hammer, tap the shift rail into the shift fork and the intermediate case.

    Object Number: 811476 Size: SH
  31. Install the 1st/reverse shift fork and rail.
    32. 31.1. The part numbered end goes up on the shift rail.
    31.2. Install the shift fork to the 1st/reverse gear synchronizer hub.
    31.3. Move the interlock plate towards 6th gear shift rail.
    31.4. Using a soft-face hammer, tap the shift rail into the shift fork and the intermediate case.

    Object Number: 811466 Size: SH
  32. Install the NEW roll pins in the 6th gear shift fork (2). A roll pin goes in each hole.
  33. Install the NEW roll pins in the 1st/reverse gear shift fork (1). A roll pin goes in each hole.

    34. Object Number: 724351 Size: SH
  34. If removed, install the shift block on the main shift rail.
    35. 34.1. The part numbers on the shift block, and the part number on the shift rail, face the same direction.
    34.2. Install the NEW large diameter roll pin.
    34.3. Install the NEW small diameter roll pin, with the roll pin split 180 degrees from the large roll pin split.

    Object Number: 662001 Size: SH
  35. Install the front internal shift lever on the main shift rail.
    36. • Align the roll pin or lever end, toward the part numbered end of the shift rail.
    • Do not install the roll pins.
  36. With the part numbered end pointing up, install the main shift rail.

    37. Object Number: 724177 Size: SH
  37. Align the shift block teeth on the main shift rail with the shift interlock plate.

    38. The center tooth on the shift block will install between the two teeth on the shift interlock plate.

  38. Position the front internal shift lever to align with the notch in the 2nd/3rd shift rail.

    39. Object Number: 661262 Size: SH
  39. Install the NEW roll pins in the internal shift control front lever.
    40. 39.1. Install the large diameter roll pin.
    39.2. Align the split on the roll pin away from the transmission.
    39.3. Install the small diameter roll pin inside of the large diameter roll pin.
    39.4. Align the split on the roll pin toward the transmission.

    Object Number: 661975 Size: SH
  40. Install the internal shift control rear lever on the main shift rail.

    41. Object Number: 661258 Size: SH
  41. Align the levers on the internal shift control rear lever with the slots in the 1st/reverse gear shift rail and the 6th gear shift rail.
  42. Install the NEW roll pins in the internal shift control rear lever.
    43. 42.1. Install the large diameter roll pin.
    42.2. Align the split on the roll pin away from the transmission.
    42.3. Install the small diameter roll pin inside of the large diameter roll pin.
    42.4. Align the split on the roll pin toward the transmission.

    Object Number: 661996 Size: SH
  43. Install the shift shaft detent plungers and springs.
  44. Apply a thin layer of gasket maker GM P/N United States 12378517, GM P/N Canada 88900757 to the shift shaft detent caps.
  45. Using an 11 mm (27/64 in) punch, install the shift shaft detent caps.

    46. Object Number: 662022 Size: SH
  46. Shift the transmission into 5th gear in order to lock the input shaft to the mainshaft.

    47. Object Number: 661238 Size: SH
  47. Install S-hooks and chain to the intermediate case.

    48. Object Number: 811522 Size: SH
  48. Position the front case on the J 45279 in order to allow the protrusion of the input shaft.
  49. Using a suitable lifting device, install the gear assembly to the front case.
    50. • Lower the gear assembly slowly in order to align the intermediate case dowel pins with the front case.
    • Do not use a sealer at this time.

    Object Number: 661237 Size: SH
  50. Install the two intermediate to front case bolts.

    51. Tighten
    Tighten the intermediate case bolts to 23 N·m (17 lb ft).


    Object Number: 821070 Size: SH
  51. Assemble the J 44739 to the intermediate case, to measure the countershaft preload.
    52. 51.1. Install the crosspiece so that the 2 holes are closer to the single bolt hole upright in the lowest notch. Do not tighten the thumbscrew.
    51.2. Install the crosspiece to the 2 bolt hole upright in the lowest notch. Do not tighten the thumbscrew.
    51.3. Using a case bolt, install the single bolt hole upright to the 7th case bolt hole from the top, on the right side of the case.
    51.4. Using a case bolt in the hole away from the upright, install the 2 bolt hole upright to the 5th case bolt hole from the top, on the left side of the case.
    51.5. Tighten the crosspiece thumbscrews.

    Object Number: 724197 Size: SH
  52. Use the following procedure in order to measure the countershaft bearing clearance.
    53. 52.1. Install the J 26900-12 or the J 29763 in the J 44739 .
    52.2. Adjust the J 26900-12 or the J 29763 to zero.
    52.3. Using a suitable prying tool, lift up the countershaft.
    52.4. Record the dial indicator reading. This is the countershaft bearing clearance.
  53. Using the following formula, establish the shim thickness required for the countershaft bearing preload:
    54. 53.1. Add the mainshaft preload specification 0.02-0.09 mm (0.0008-0.0035 in) to the countershaft bearing clearance measurement.
    53.2. The total is the shim thickness required under the countershaft bearing race in order to set the bearing preload.

    Example

       • 1.8 mm (0.070 in) mainshaft bearing clearance measurement
       • Plus 0.02-0.09 mm (0.0008-0.0035 in) countershaft preload specification
       • Equals 1.82-1.89 mm (0.070-0.074 in) shim thickness required

    Object Number: 821071 Size: SH
  54. Assemble the J 44739 to the intermediate case, to measure the mainshaft preload.
    55. 54.1. Install the crosspiece so that the 2 holes are closer to the single bolt hole upright in the upper notch, for RWD, or center notch for 4WD. Do not tighten the thumbscrew.
    54.2. Install the crosspiece to the 2 bolt hole upright in the upper notch, for RWD, or center notch for 4WD. Do not tighten the thumbscrew.
    54.3. Using a case bolt, install the single bolt hole upright to the 3rd case bolt hole from the top, on the right side of the case.
    54.4. Using a case bolt in the hole closest to the upright, install the upright with the 2 bolt holes to the 6th case bolt hole from the top, on the left side of the case.
    54.5. Tighten the thumbscrews.

    Object Number: 724199 Size: SH
  55. Use the following procedure in order to measure the mainshaft bearing clearance.
    56. 55.1. Install the J 26900-12 or the J 29763 in the J 44739 .
    55.2. Adjust the J 26900-12 or the J 29763 to zero.
    55.3. Using a suitable prying tool, lift up the mainshaft.
    55.4. Record the dial indicator reading. This is the mainshaft bearing clearance measurement.
  56. Using the following formula, establish the shim thickness required for the mainshaft bearing preload:
    57. 56.1. Measure the input shaft bearing oil deflector thickness. Record this measurement.
    56.2. Subtract the oil deflector measurement from the mainshaft bearing clearance measurement.
    56.3. Add the mainshaft preload specification 0.02-0.09 mm (0.0008-0.0035 in).
    56.4. The total is the shim thickness required under the input bearing race in order to set the bearing preload.

    Example

       • 0.50 mm (0.020 in) oil deflector thickness
       • minus 2.2 mm (0.087 in) mainshaft bearing clearance measurement
       • equals 1.7 mm (0.067 in)
       • plus 0.02-0.09 mm (0.008-0.0035 in) mainshaft preload specification
       • equals 1.75 mm (0.069 in) shim thickness required

    Object Number: 661237 Size: SH
  57. Remove the 2 bolts retaining the intermediate case to the front case.

    58. Object Number: 811522 Size: SH
  58. Using S-hooks, a chain, and a suitable lifting device, remove the gear assembly.

    59. Object Number: 722220 Size: SH
  59. Using the J 44736  (1) and the J 44733  (2), remove the mainshaft front bearing race.
    60. 59.1. Expand the J 44733  (2) to fit securely under the bearing race.
    59.2. Align the legs of the J 44733 to rest on the webbing of the case.
    59.3. Remove the mainshaft front bearing race.

    Object Number: 722224 Size: SH
  60. Using the J 44736  (1) and the J 44728  (2), remove the countershaft front bearing race.
    61. 60.1. Install the J 44728  (2) in order for the fingers to fit in the notches in the case.
    60.2. Expand the J 44728  (2) to fit securely in the bearing race.
    60.3. Align the legs of the J 44736 to rest on the webbing of the case.
    60.4. Remove the countershaft front bearing race.

    Object Number: 722853 Size: SH
  61. Using the J 25070 , heat the front case for 10-15 minutes.

    62. Object Number: 724204 Size: SH
  62. Install the required shims for the countershaft bearing preload.

    63. Object Number: 722852 Size: SH

    Important: Install the bearing races with the front case still hot. Do not allow the front case to cool.

  63. Using the J 8092  (1), the J 21465-13  (2), and the J 44745  (3), install the countershaft front bearing race.

    64. Object Number: 722690 Size: SH
  64. Install the oil trough.

    65. Object Number: 722688 Size: SH
  65. Install the required shims for the mainshaft bearing preload.
  66. Install the input shaft gear oil deflector.

    67. Object Number: 722851 Size: SH
  67. Using the J 8092  (1), the J 21465-13  (2), and the J 44746  (3), install the mainshaft front bearing race.
  68. Allow the front case to cool.

    69. Object Number: 811522 Size: SH
  69. Apply a thin layer of gasket maker GM P/N United States 12378517, GM P/N Canada 88900757, to the sealing surface of the front case.
  70. Using a suitable lifting device, install the gear assembly to the front case.

    71. Object Number: 661237 Size: SH
  71. Install the two intermediate case to front case bolts.

    72. Tighten
    Tighten the intermediate case to front case bolts to 23 N·m (17 lb ft).


    Object Number: 811458 Size: SH
  72. Apply a thin layer of gasket maker GM P/N United States 12378517, GM P/N Canada 88900757 to the sealing surface of the rear case.
  73. Install the rear case on to the intermediate case.
  74. Using a soft-face hammer, tap down on the rear case to seat the dowel pins. Do not use the bolts to draw the case together.
  75. Install the required brackets and the bolts retaining the rear case.

    76. Tighten
    Tighten the rear case bolts in a crossover sequence to 23 N·m (17 lb ft).


    Object Number: 661234 Size: SH
  76. Apply a thin layer of threadlocker GM P/N United States 12345382, GM P/N Canada 10953489 to the threads of the shift shaft detent sleeve.
  77. Install the shift shaft detent plunger and sleeve.

    78. Tighten
    Tighten the detent sleeve to 65 N·m (48 lb ft).


    Object Number: 811452 Size: SH
  78. Install the vehicle speed sensor (VSS) with an O-ring seal in the rear case.
  79. Install the VSS bolt.

    80. Tighten
    Tighten the VSS bolt to 20 N·m (15 lb ft).


    Object Number: 811447 Size: SH

    Important: The ZF S6-650 manual transmission is used with 4 different applications, depending on the engine or if equipped with the driveline parking brake. The assemble procedures are the same for all 4 applications, except where indicated.

    The 4 different applications are as follows:

       • 8.2L engine with driveline parking brake - uses 1480 series size yoke and 4 bolt hole park brake drum
       • 8.2L engine without driveline parking brake - uses 1480 series size yoke
       • 6.6L engine with driveline parking brake - uses 1550 series size yoke and 8 bolt hole park brake drum
       • 6.6L engine without driveline parking brake - uses 1550 series size yoke

  80. If equipped, install the parking brake cable bracket.
  81. If equipped, install the bolts retaining the parking brake cable bracket.

    82. Tighten
    Tighten the bracket bolts to 23 N·m (17 lb ft).


    Object Number: 811440 Size: SH
  82. If equipped, lubricate the hole, for the parking brake cam lever in the case, with chassis grease.
  83. If equipped, install, as an assembly, the parking brake shoes, bracket, and cam lever.
  84. If equipped, install the bolts retaining the parking brake shoe bracket to the rear case.

    85. Tighten
    Tighten the shoe bracket bolts to 120 N·m (89 lb ft).


    Object Number: 811515 Size: SH
  85. Using the J 44732 , install the rear oil seal. The seal installer will install the seal at the correct depth.
  86. Lightly lubricate the seal surface with J 36850 or equivalent.

    87. Object Number: 811518 Size: SH

    Important: If equipped with the driveline parking brake, the original drum and yoke come as a balanced assembly. Ensure to align the mark during disassembly, if using the drum and yoke again.

  87. If removed, install the parking brake drum to the propeller shaft yoke.
  88. If 8.2L engine, install the parking brake drum to propeller shaft yoke bolts and washers.

    89. Tighten
    Tighten the 4 bolt drum bolts to 145 N·m (107 lb ft).


    Object Number: 811364 Size: SH
  89. Install the parking brake drum/yoke assembly on the yoke flange.

    90. Object Number: 1286684 Size: SH
  90. If 6.6L engine, install the parking brake drum to propeller shaft yoke bolts and nuts.

    91. Tighten
    Tighten the 8 bolt drum nuts to 60 N·m (44 lb ft).


    Object Number: 811362 Size: SH
  91. Install a NEW propeller shaft yoke nut.

    92. Object Number: 811358 Size: SH
  92. Install the J 8614-01 in order to hold the transmission shaft from rotating. Use 2 3/8 NF bolts to hold the J 8614-01 to the propeller shaft yoke.

    93. Tighten
    Tighten the NEW propeller shaft yoke nut to 330 N·m (244 lb ft).


    Object Number: 811357 Size: SH
  93. Install the clutch cable bracket and the bolts.

    94. Tighten
    Tighten the clutch cable bracket bolts to 46 N·m (34 lb ft).


    Object Number: 811355 Size: SH
  94. If the lower shift lever requires installation before installing in the vehicle, apply a thin layer of gasket maker GM P/N United States 12378517, GM P/N Canada 88900757 to the sealing surface of the lower shift control lever.
  95. Install the lower shift control lever. Ensure the word FRONT on the shift control housing is to the front of the transmission.
  96. Install the lower shift control lever bolts.

    97. Tighten
    Tighten the lower shift control lever bolts to 23 N·m (17 lb ft).


    Object Number: 811340 Size: SH
  97. Move the transmission to the horizontal position.
  98. Remove the J 45279 from the front of the transmission.

    99. Object Number: 811520 Size: SH

    Important: When installing the input shaft seal, there is not a stop for the seal in the case. Using the seal tools installs the seal at the proper depth. Hitting too hard on the seal tools can misplace the seal at the proper depth.

  99. Using the J 22828 and the J 45277 , install the input shaft seal.
    100. 99.1. Position the seal in the front case with the open side to the transmission.
    99.2. Lightly tap on the J 22828 to install the seal.

    Object Number: 811343 Size: SH
  100. Install the quill tube.
  101. Install the 6 bolts holding the quill tube to the front of the transmission.

    102. Tighten
    Tighten the quill tube bolts to 23 N·m (17 lb ft).

  102. Shift the transmission through all of the gears to ensure proper shifting.
  103. Rotate the transmission by the input shaft.

    104. There should be resistance to turn.


    Object Number: 811334 Size: SH
  104. Install the transmission drain plug and O-ring seal. Ensure the O-ring seal is not damaged.

    105. Tighten
    Tighten the drain plug to 35 N·m (26 lb ft).

  105. If equipped with a PTO, install the PTO using the manufacturers recommended procedures for the proper operation.