INFO. ON ELECT. SHIFT TRANSFER CASE REPAIR PROCEDURE. GMC Truck Jimmy

REVISION 05/21/93

THIS BULLETIN IS BEING REVISED TO INCLUDE THE REPAIR PROCEDURE.

REVISION: 03/08/94

THIS BULLETIN IS BEING REVISED TO INCLUDE THE SHIFT SECTOR PART NUMBER AND ADD ANOTHER CONDITION. PREVIOUS DIVISIONAL PUBLICATION NUMBERS WERE:

--------------------------------------------------------------------- DIV BULLETIN # PUBLISH DATE CHEVROLET 93-225-7D 6/17/93 GMC TRUCK 93-7D-88 6/08/93 GM CANADA 93-7D-102 9/27/93 ----------------------------------------------------------------------

SUBJECT: ELECTRIC SHIFT TRANSFER CASE (NP233E) DOES NOT SHIFT OUT OF 4-LOW, GRINDS WHEN SHIFTING FROM 4-LOW TO 4-HIGH, OR SLIPS OUT OF 4-HIGH (REVISED RANGE SHIFT FORK, HUB KIT, AND SHIFT SECTOR RELEASED)

MODELS: 1992-93 CHEVROLET AND GMC TRUCK T TRUCKS EQUIPPED WITH ELECTRIC SHIFT TRANSFER CASE (RPO NP1)

CONDITION:

SOME OWNERS MAY EXPERIENCE THE FOLLOWING CONDITIONS:

1. GRINDS WHEN SHIFTING FROM 4-LOW TO 4-HIGH. 2. WILL NOT SHIFT OUT OF 4-LOW. 3. SLIPS OUT OF 4-HIGH (USUALLY RESULTS IN RATCHET NOISE).

CAUSE:

THESE CONDITIONS MAY BE DUE TO THE RANGE SHIFT FORK AND RANGE SHIFT HUB PREVENTING PROPER SHIFT ENGAGEMENT OF THE PLANETARY CARRIER AND THE INPUT GEAR.

CORRECTION:

A REVISED RANGE SHIFT FORK ASSEMBLY (INCLUDING PADS), INPUT GEAR, AND RANGE SHIFT HUB SERVICE KIT (TRANSFER CASE FIELD SERVICE KIT, P/N 15971058) TO CORRECT THESE CONDITIONS ARE NOW AVAILABLE. THE PARTS HAVE BEEN REVISED TO ALLOW FOR PROPER SHIFT ENGAGEMENT. IN ADDITION, A REVISED SHIFT SECTOR (P/N 12544302) SHOULD BE INSTALLED IN CONJUNCTION WITH THE TRANSFER CASE FIELD SERVICE KIT.

SERVICE PROCEDURE:

PLEASE REFER TO SECTION 7D TRANSFER CASE IN THE APPROPRIATE LIGHT DUTY TRUCK UNIT REPAIR MANUAL (DISASSEMBLY AND ASSEMBLY OF INTERNAL COMPONENTS).

SERVICE PARTS INFORMATION:

PART NUMBER DESCRIPTION QUANTITY 15971058 KIT-TRANSFER CASE FIELD SERVICE 1 12544302 SHIFT SECTOR 1

PARTS ARE EXPECTED TO BE AVAILABLE FROM GMSPO ON 3/7/94.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY USE:

LABOR OPERATION LABOR TIME ------------------- ---------------- K4400 SEE APPLICABLE LABOR TIME GUIDE

FIGURES: 0

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.