MANUAL TRANS. SHIFTS HARD INTO OR OUT OF GEAR

SUBJECT:MANUAL TRANSMISSION SHIFTS HARD INTO OR OUT OF GEAR (REPLACE SHIFT COVER HOUSING)

MODELS: 1990-94 CHEVROLET AND GMC TRUCK C5H, C6H, C7H, 6P, 7S, 7T, AND 6T CHASSIS WITH EATON FS SERIES MANUAL TRANSMISSIONS (RPO'S MSG, MSC, MSA, MPU, MPV, MMO, MKO, MLO, AND MWO)

CONDITION:

MANUAL TRANSMISSION HARD TO SHIFT INTO OR OUT OF GEAR. THIS CONDITION USUALLY OCCURS IN FOURTH, FIFTH AND/OR SIXTH GEARS.

CAUSE:

DETENT BORES IN THE TRANSMISSION SHIFT COVER HOUSING MAY ELONGATE WHICH COULD CAUSE THE DETENT BALL AND SHIFT RAIL TO BIND IN THE BORE WHEN SHIFTING.

CORRECTION:

FOLLOW SERVICE MANUAL DIAGNOSIS CHART FOR POSSIBLE CAUSES OF HARD SHIFTING. IF SERVICE MANUAL DIAGNOSIS CHART DOES NOT LOCATE CAUSE OF HARD SHIFT CONCERN, INSPECT SHIFT COVER HOUSING DETENT BORES FOR ELONGATION. A SHIFT BAR HOUSING WITH AN ELONGATED DETENT BORE IN THE FOUR TO FIVE SPEED RAIL ON A FIVE SPEED TRANSMISSION IS ILLUSTRATED IN FIGURE 1. IF BORES ARE ELONGATED, INSTALL TRANSMISSION SHIFT COVER HOUSING WITH STEEL SLEEVES IN THE FOUR TO FIVE SPEED RAIL ON FIVE SPEED TRANSMISSIONS AND THE FIVE TO SIX SPEED RAIL ON SIX SPEED TRANSMISSIONS.

SERVICE PROCEDURE:

IMPORTANT: THIS BULLETIN DOES NOT APPLY TO EATON FS-7206 MANUAL TRANSMISSIONS (RPO MW5). THE FS-7206 TRANSMISSION HAS A CAST IRON SHIFT HOUSING AND DOES NOT REQUIRE STEEL SLEEVES IN THE HIGH SPEED RAIL DETENT BORE.

1. FOLLOW HARD SHIFTING DIAGNOSIS CHART IN SECTION 7B OF THE TOPKICK/KODIAK AND MEDIUM DUTY FORWARD CONTROL CHASSIS SERVICE MANUAL FOR POSSIBLE CAUSES OF HARD SHIFTING. 2. IF SERVICE MANUAL DIAGNOSIS CHART DOES NOT LOCATE CAUSE OF HARD SHIFTING CONCERN, INSPECT SHIFT COVER HOUSING DETENT BORES FOR ELONGATION BY FOLLOWING THE STEPS BELOW. 3. REMOVE ENGINE ACCESS COVER FOLLOWING ENGINE ACCESS COVER REPLACEMENT IN SECTION 10A4 OF THE TOPKICK/KODIAK AND MEDIUM DUTY FORWARD CONTROL CHASSIS SERVICE MANUAL. 4. SHIFT TRANSMISSION INTO NEUTRAL.

IMPORTANT: SHIFTING THE TRANSMISSION INTO NEUTRAL WILL AID WHEN RE-INSTALLING THE SHIFT BAR HOUSING TO THE TRANSMISSION.

5. WORKING THROUGH THE ENGINE ACCESS COVER, REMOVE RETAINERS, SHIFT LEVER ISOLATOR BUSHINGS AND SHIFT LEVER PIVOT PIN FROM THE SHIFT LEVER AT THE TRANSMISSION (FIGURE 2, ITEMS 1, 2 AND 3). 6. TIE SHIFT LEVER AWAY FROM THE TRANSMISSION AND SHIFT BAR HOUSING. 7. REMOVE ELECTRICAL CONNECTORS FROM THE SHIFT BAR HOUSING AS REQUIRED. 8. REMOVE BOLTS ATTACHING SHIFT COVER HOUSING TO TRANSMISSION. 9. REMOVE SHIFT COVER HOUSING INCLUDING SHIFT YOKES AND RAILS FROM THE TRANSMISSION. PULL SHIFT COVER HOUSING THROUGH THE ENGINE ACCESS COVER. 10. REMOVE GASKET MATERIAL BETWEEN COVER AND TRANSMISSION. 11. PLACE THE SHIFT BAR HOUSING ON A FLAT, CLEAN SURFACE.

IMPORTANT: DURING DISASSEMBLY OF THE SHIFT BAR HOUSING, LAY ALL PARTS ON A CLEAN BENCH IN ORDER OF REMOVAL. THIS WILL AID DURING RE-INSTALLATION. REMEMBER TO REMOVE THE INTERLOCK AND DETENT BALLS BEFORE REMOVING THE SPRINGS. DISASSEMBLY AND RE- ASSEMBLY PROCEDURES VARY SLIGHTLY DEPENDING ON THE TRANSMISSION MODEL. DEPENDING ON THE MODEL, FOLLOW ONLY ONE OF THE FOLLOWING PROCEDURES. FOR REPRESENTATIVE FIGURES OF SHIFT YOKE ASSEMBLIES AND ASSOCIATED PARTS FOR FS-5005 AND FS-5106 SERIES TRANSMISSIONS, REFER TO THE FS-4005 AND FS-6105 SERIES PROCEDURE BELOW.

FOR FS-4005 AND FS-6105 SERIES TRANSMISSIONS:

12. IN ORDER TO REMOVE THE FRONT YOKE BAR SUPPORT AND BOLTS, SHIFT THE 4TH-5TH YOKE ASSEMBLY INTO 4TH GEAR POSITION. 13. REMOVE FRONT AND REAR SHIFT BAR RETAINERS AND BOLTS (FIGURE 3, ITEM 1). 14. REMOVE 1ST-REVERSE YOKE ASSEMBLY (FIGURE 4, ITEM 1). 15. REMOVE 2ND-3RD YOKE ASSEMBLY AND INTERLOCK PIN (FIGURE 5, ITEM 1). 16. REMOVE 4TH-5TH YOKE ASSEMBLY (FIGURE 6, ITEM 1). 17. REMOVE THE INTERLOCK BALLS, DETENT BALLS AND SPRINGS (FIGURE 6, ITEM 2). 18. REMOVE REVERSE LIGHT SWITCH INCLUDING SPRING AND TWO BALLS FROM SHIFT BAR HOUSING. 19. FOR FS-4005 SERIES, REMOVE THE REVERSE PLUNGER RETAINING PLUG AND GASKET (FIGURE 7). 20. REMOVE THE REVERSE PLUNGER SPRING, STOP AND PLUNGER. 21. REMOVE SHIFT LEVER TOWER FROM SHIFT BAR HOUSING. 22. FOR FS-4005 SERIES, INSTALL THE REVERSE PLUNGER IN NEW SHIFT COVER HOUSING. 23. INSTALL REVERSE PLUNGER SPRING, STOP, GASKET AND PLUG IN NEW SHIFT COVER HOUSING. TIGHTEN PLUG TO 11-16 N.M (8-12 LBS. FT.) (FIGURE 7). 24. INSTALL THE INTERLOCK BALLS, DETENT BALLS AND SPRINGS IN NEW SHIFT COVER HOUSING IN THE FOLLOWING ORDER: (1) POSITION THE THREE BALLS IN THE REVERSE LIGHT SWITCH BORE OF THE NEW SHIFT COVER HOUSING; (2) INSTALL 1ST-REVERSE DETENT SPRING AND BALL; (3) POSITION TWO BALLS IN ADJACENT CROSS BORE; (4) INSTALL 2ND- 3RD DETENT SPRING AND BALL; (5) POSITION TWO BALLS IN ADJACENT CROSS BORE; (6) INSTALL 4TH-5TH DETENT SPRING AND BALL. 25. POSITION 1ST-REVERSE YOKE IN NEW SHIFT COVER HOUSING ASSEMBLY (FIGURE 4, ITEM 1). 26. INSTALL INTERLOCK PIN IN 2ND-3RD YOKE ASSEMBLY (FIGURE 5, ITEM 1). 27. POSITION 2ND-3RD YOKE IN HOUSING ASSEMBLY. 28. POSITION 4TH-5TH YOKE IN HOUSING ASSEMBLY (FIGURE 6, ITEM 1). 29. POSITION FRONT AND REAR SHIFT BAR RETAINERS (AND MIDDLE FOR FS- 6105 SERIES) IN PROPER POSITION (FIGURE 3, ITEM 1). 30. INSTALL BOLTS IN REAR (AND MIDDLE FOR FS-6105 SERIES) SHIFT BAR RETAINER. TIGHTEN BOLTS TO 27-34 N.M (20-25 LBS. FT.). 31. CAREFULLY SHIFT THE 4TH-5TH YOKE REARWARD (INTO 4TH GEAR POSITION). 32. INSTALL THE BOLTS IN THE FRONT SHIFT BAR RETAINER. TIGHTEN TO 27-34 N.M (20-25 LBS. FT.). 33. INSTALL SHIFT LEVER TOWER TO NEW SHIFT BAR HOUSING. BE SURE TO INSTALL A NEW SHIFT LEVER TOWER GASKET BETWEEN THE SHIFT COVER HOUSING AND THE SHIFT LEVER TOWER. TORQUE BOLTS TO 27-34 N.M (20-25 LBS. FT.). 34. INSTALL REVERSE LIGHT SWITCH INCLUDING SPRING AND TWO BALLS ON SHIFT BAR HOUSING. CONTINUE WITH STEP NUMBER 85 BELOW.

FS-5005 SERIES TRANSMISSIONS:

35. IN ORDER TO REMOVE THE FRONT YOKE BAR SUPPORT AND BOLTS, SHIFT THE 4TH-5TH YOKE ASSEMBLY INTO 4TH GEAR POSITION. 36. REMOVE FRONT AND REAR SHIFT BAR RETAINERS AND BOLTS. 37. REMOVE 4TH-5TH YOKE ASSEMBLY. 38. REMOVE 2ND-3RD YOKE ASSEMBLY AND INTERLOCK PIN. 39. REMOVE 1ST-REVERSE BAR ASSEMBLY AND, IF NECESSARY, 1ST-REVERSE BAR FRONT SPACER. 40. FROM THE 1ST-REVERSE YOKE ASSEMBLY, REMOVE THE 1ST-REVERSE LOCK PIN. 41. REMOVE THE 1ST-REVERSE YOKE ASSEMBLY. 42. REMOVE THE 1ST-REVERSE ACTUATOR. 43. REMOVE THE FOUR INTERLOCK BALLS, THE THREE DETENT BALLS, THE THREE BACK UP LIGHT SWITCH BALLS AND THE THREE SPRINGS. 44. REMOVE THE REVERSE PLUNGER RETAINING PLUG AND GASKET. 45. REMOVE REVERSE LIGHT SWITCH INCLUDING SPRING AND TWO BALLS FROM SHIFT BAR HOUSING. 46. REMOVE THE REVERSE PLUNGER SPRING, STOP AND PLUNGER. 47. REMOVE SHIFT LEVER TOWER FROM SHIFT BAR HOUSING. 48. INSTALL THE REVERSE PLUNGER IN NEW SHIFT COVER HOUSING. 49. INSTALL REVERSE PLUNGER SPRING, STOP, GASKET AND PLUG. TIGHTEN PLUG TO 11-16 N.M (8-12 LBS. FT.). 50. INSTALL THE INTERLOCK BALLS, DETENT BALLS AND SPRINGS IN NEW SHIFT COVER HOUSING IN THE FOLLOWING ORDER: (1) POSITION THE THREE BALLS IN THE REVERSE LIGHT SWITCH BORE OF THE NEW SHIFT COVER HOUSING; (2) INSTALL 1ST-REVERSE DETENT SPRING AND BALL; (3) POSITION TWO BALLS IN ADJACENT CROSS BORE; (4) INSTALL 2ND- 3RD DETENT SPRING AND BALL; (5) POSITION TWO BALLS IN ADJACENT CROSS BORE; (6) INSTALL 4TH-5TH DETENT SPRING AND BALL. 51. OVER THE ACTUATOR PIN, SEAT THE 1ST-REVERSE ACTUATOR. 52. POSITION 1ST-REVERSE YOKE ASSEMBLY IN THE HOUSING. 53. INSTALL THE 1ST-REVERSE LOCK PIN IN THE YOKE ASSEMBLY. 54. POSITION 1ST-REVERSE BAR ASSEMBLY IN THE HOUSING. 55. INSTALL THE 2ND-3RD YOKE INTERLOCK PIN. 56. POSITION THE 2ND-3RD YOKE IN THE HOUSING ASSEMBLY. 57. POSITION THE 4TH-5TH YOKE IN THE HOUSING ASSEMBLY. 58. POSITION FRONT AND REAR SHIFT BAR RETAINERS AND BOLTS. 59. INSTALL BOLTS IN REAR RETAINER. TIGHTEN TO 27-34 N.M (20-25 LBS. FT.). 60. CAREFULLY SHIFT THE 4TH-5TH YOKE REARWARD (INTO 4TH GEAR POSITION). 61. INSTALL BOLTS TO FRONT RETAINER. TIGHTEN BOLTS TO 27-34 N.M (20-25 LBS. FT.). 62. INSTALL SHIFT LEVER TOWER TO NEW SHIFT BAR HOUSING. BE SURE TO INSTALL A NEW SHIFT LEVER TOWER GASKET BETWEEN THE SHIFT COVER HOUSING AND THE SHIFT LEVER TOWER. TORQUE BOLTS TO 27-34 N.M (20-25 LBS. FT.). 63. INSTALL REVERSE LIGHT SWITCH INCLUDING SPRING AND TWO BALLS TO SHIFT BAR HOUSING. CONTINUE WITH STEP NUMBER 85 BELOW.

FS-5106 SERIES:

64. IN ORDER TO REMOVE THE FRONT SHIFT BAR RETAINER, SHIFT THE 5TH- 6TH YOKE ASSEMBLY INTO THE 5TH GEAR POSITION (REARWARD). 65. REMOVE BOLTS AND SHIFT BAR RETAINERS. 66. REMOVE REVERSE YOKE ASSEMBLY. 67. REMOVE 1ST-2ND YOKE ASSEMBLY AND INTERLOCK PIN. 68. REMOVE 3RD-4TH YOKE ASSEMBLY AND INTERLOCK PIN. 69. REMOVE 5TH-6TH YOKE ASSEMBLY. 70. REMOVE SHIFT LEVER TOWER FROM SHIFT BAR HOUSING. 71. REMOVE REVERSE LIGHT SWITCH INCLUDING SPRING AND TWO BALLS FROM SHIFT BAR HOUSING. 72. INSTALL THE INTERLOCK BALLS, DETENT BALLS AND SPRINGS IN THE SHIFT COVER HOUSING WITH STEEL SLEEVES IN THE FOLLOWING ORDER: (1) POSITION THE THREE BALLS IN THE REVERSE LIGHT SWITCH BORE OF THE NEW SHIFT COVER HOUSING; (2) INSTALL 1ST-REVERSE DETENT SPRING AND BALL; (3) POSITION TWO BALLS IN ADJACENT CROSS BORE; (4) INSTALL 2ND-3RD DETENT SPRING AND BALL; (5) POSITION TWO BALLS IN ADJACENT CROSS BORE; (6) INSTALL 4TH-5TH DETENT SPRING AND BALL. 73. POSITION REVERSE YOKE IN HOUSING ASSEMBLY. 74. INSTALL INTERLOCK PIN IN 1ST-2ND YOKE ASSEMBLY. 75. POSITION 1ST-2ND YOKE IN HOUSING ASSEMBLY. 76. INSTALL INTERLOCK PIN IN 3RD-4TH YOKE ASSEMBLY. 77. POSITION 3RD-4TH YOKE IN HOUSING ASSEMBLY. 78. POSITION 5TH-6TH YOKE IN HOUSING ASSEMBLY. 79. POSITION FRONT, MIDDLE AND REAR SHIFT BAR RETAINERS. 80. INSTALL BOLTS IN THE MIDDLE AND REAR SHIFT BAR RETAINERS. TIGHTEN TO 27-34 N.M (20-25 LBS. FT.). 81. CAREFULLY SHIFT THE 5TH-6TH YOKE REARWARD (INTO THE 5TH GEAR POSITION). 82. INSTALL CAP SCREWS IN FRONT SHIFT BAR RETAINER. TIGHTEN TO 27-34 N.M (20-25 LBS. FT.). 83. INSTALL SHIFT LEVER TOWER TO NEW SHIFT BAR HOUSING. BE SURE TO INSTALL A NEW SHIFT LEVER TOWER GASKET BETWEEN THE SHIFT COVER HOUSING AND THE SHIFT LEVER TOWER. TORQUE BOLTS TO 27-34 N.M (20-25 LBS. FT.). 84. INSTALL REVERSE LIGHT SWITCH INCLUDING SPRING AND TWO BALLS TO SHIFT BAR HOUSING. CONTINUE WITH STEP NUMBER 85 BELOW.

ALL FS SERIES TRANSMISSIONS (REINSTALL SHIFT BAR HOUSING TO TRANSMISSION)

85. INSTALL NEW SHIFT HOUSING GASKET MATERIAL BETWEEN THE SHIFT BAR HOUSING AND TRANSMISSION. 86. INSTALL SHIFT BAR HOUSING TO TRANSMISSION THROUGH THE ENGINE ACCESS OVER. 87. INSTALL SHIFT BAR HOUSING BOLTS TO THE TRANSMISSION.

NOTICE: THERE ARE TWO DIFFERENT BOLT LENGTHS USED ON THE SHIFT COVER HOUSING. WHEN REINSTALLING THE SHIFT COVER HOUSING TO TRANSMISSION, BE SURE TO USE 1 1/2 INCH (38MM) BOLTS ON HOLES WITH LIFTING EYES.

88. INSTALL RETAINERS, SHIFT LEVER ISOLATOR BUSHINGS AND SHIFT LEVER PIVOT PIN TO THE SHIFT LEVER AT THE TRANSMISSION (FIGURE 2, ITEMS 1, 2 AND 3). 89. INSTALL ENGINE ACCESS COVER FOLLOWING ENGINE ACCESS COVER REPLACEMENT IN SECTION 10A4 OF THE TOPKICK/KODIAK AND MEDIUM DUTY FORWARD CONTROL CHASSIS SERVICE MANUAL. 90. VERIFY TRANSMISSION FLUID IS TO THE LEVEL OF THE FILLER PLUG OPENING. IF REQUIRED, ADD FLUID TO BRING TO PROPER LEVEL.

SERVICE PARTS INFORMATION

P/N DESCRIPTION QTY

12380361 SHIFT RAIL HOUSING FS4005 SERIES 1 (RPO'S MSA, MSC AND MSG) 12380365 SHIFT RAIL HOUSING FS-6105 1 (RPO'S MKO AND MLO) 12380367 SHIFT RAIL HOUSING FS-5106 AND FS-6206 SERIES 1 (RPO'S MMO AND MWO) 12380363 SHIFT RAIL HOUSING FS-5005 SERIES 1 (RPO'S MPU, MPV) 15510639 SHIFT HOUSING GASKET FS-4005 SERIES 1 15578612 SHIFT HOUSING GASKET FS-5106, FS-6105 AND 1 FS-6206 SERIES 3912240 SHIFT HOUSING GASKET FS-5005 SERIES 1 12345724 1 GALLON EATON MANUAL TRANSMISSION 1 SYNTHETIC LUBRICANT 12545390 SHIFT LEVER TOWER GASKET 1

PARTS ARE EXPECTED TO BE AVAILABLE FROM GMSPO ON 11/7/94.

WARRANTY INFORMATION

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OP DESCRIPTION LABOR TIME K2240 COVER AND/OR GASKET 1.4 HRS. TRANS SHIFT HOUSING REMOVE AND REPLACE

FIGURES: 7

CAPTIONS: FIGURE 1 - SHIFT BAR HOUSING FIGURE 2 - SHIFT LEVER BUSHINGS, PIVOT PIN AND RETAINERS FIGURE 3 - FRONT AND REAR SHIFT BAR RETAINERS AND BOLTS FIGURE 4 - 1ST - REVERSE YOKE ASSEMBLY FIGURE 5 - 2ND- 3RD YOKE ASSEMBLY AND INTERLOCK PIN FIGURE 6 - 4TH - 5TH YOKE ASSEMBLY, INTERLOCK BALLS, DETENT BALLS AND SPRINGS FIGURE 7 - REVERSE PLUNGER ASSEMBLY FOR FS-4005 AND FS-5005 SERIES TRANSMISSIONS

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