INFORMATION ON CENTER SUPPORT BOLT - NEW SERVICE PACKAGE

SUBJECT: INFORMATION ON CENTER SUPPORT BOLT - NEW SERVICE PACKAGE

MODELS: 1990-94 CHEVROLET AND GMC TRUCK C/K, R/V, P TRUCKS AND G VAN

TRANSMISSION APPLICATIONS: 1990 HYDRA-MATIC 3L80/3L80-HD AND 1991-1994 4L80-E/4L80-EHD

SERVICE INFORMATION: (FIGURE 2) A NEW CENTER SUPPORT BOLT HAS BEEN RELEASED FOR SERVICE TO ALLOW THE CENTER SUPPORT TO BE RECONDITIONED ONE TIME FOR ALL HYDRA-MATIC 4L80-E/4L80-EHD AND FOR ALL 3L80/3L80-HD TRANSMISSIONS BUILT MARCH 1, 1989 (JULIAN DATE 060) AND LATER. REFER TO 3L80/3L80-HD CORPORATE BULLETIN #077134 (CHEVROLET 90-357-7A; GMC TRUCK 90-7A-105; GM OF CANADA 9073L80104) CONCERNING CHANGES TO THE CASE AND CENTER SUPPORT BOLT.

BEGINNING ON DECEMBER 21, 1993 (JULIAN DATE 355), SOME 4L80-E/4L80-EHD AND 3L80/3L80-HD SRTA'S (SERVICE REPLACEMENT TRANSMISSION ASSEMBLY) ARE BEING BUILT WITH THE NEW SERVICE BOLT. THE NEW SERVICE BOLT IS COATED WITH ZINC CHROMATE AND IS YELLOW IN COLOR. THE CURRENT PRODUCTION BOLT IS PHOSPHATE COATED AND IS BLACK IN COLOR. THE CURRENT PRODUCTION BOLT AND THE SERVICE BOLT ARE THE SAME LENGTH.

WHEN SERVICING A 4L80-E/4L80-EHD OR A 3L80/3L80HD BUILT AFTER MARCH 1, 1990, THE CENTER SUPPORT CAN BE RECONDITIONED ONE TIME USING J 39919, CENTER SUPPORT REAMER AND GAUGE AND THE SERVICE BOLT PACKAGE. IF THE TRANSMISSION ASSEMBLY CONTAINS THE SERVICE BOLT OR IF THE 3L80/3L80-HD CONTAINS THE SHORT PRODUCTION CENTER SUPPORT BOLT, THE CENTER SUPPORT AND BOLT MUST BE REPLACED. (REFER TO CORPORATE BULLETIN #077143.)

PARTS INFORMATION:

GMC TRUCK DEALERS SHOULD REFER TO CORPORATE BULLETIN #367106. AUTOMATIC TRANSMISSION SERVICE PROCEDURE CHANGES, PUBLISHED IN DECEMBER, 1993 FOR CORRECT SERVICE PROCEDURES FOR REPAIRS UNDER WARRANTY.

PART NUMBER NAME 24202218 SERVICE BOLT PACKAGE, CENTER SUPPORT CENTER SUPPORT SERVICE BOLT INSTRUCTION SHEET

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

INSTRUCTIONS:

THIS BOLT ALLOWS ONE TIME REUSE/REASSEMBLY OF THE CENTER SUPPORT BY ACHIEVING THE SAME LEVEL OF THREAD INTERFERENCE AS THE PRODUCTION ASSEMBLY. THE SERVICE BOLT HAS A ZINC CHROMATE (YELLOW/GOLD) PLATING TO AID IN IDENTIFICATION. THE CURRENT PRODUCTION BOLT IS THE SAME LENGTH AS THE SERVICE BOLT AND HAS A BLACK PHOSPHATE (BLACK COLOR) COATING.

NOTE: KENT-MOORE SERVICE TOOL J 39919 MUST BE USED TO RESIZE THE THREAD IN THE CENTER SUPPORT BEFORE REASSEMBLY TO THE TRANSMISSION CASE. SEE KENT MOORE INSTRUCTION SHEET FOR PROPER USE OF TOOL.

THE ASSEMBLY TORQUE FOR THE SERVICE BOLT IS 50 N.M (37 LBS. FT.). THE RUN-IN TORQUE WILL BE APPROXIMATELY HALF OF THIS VALUE.

IF THE TRANSMISSION ALREADY CONTAINS THE SERVICE BOLT (YELLOW/GOLD COLOR) OR IF THE PRODUCTION BOLT REMOVED IS SHORTER IN LENGTH (SOME 3L80/3L80-HD ONLY, REFER TO CORPORATE BULLETIN #077143) THAN THE SERVICE BOLT, THE CENTER SUPPORT BOLT THREAD CANNOT BE RESIZED AND THE CENTER SUPPORT ASSEMBLY MUST BE REPLACED.

J 39919 CENTER SUPPORT THREAD REAMER KIT (FIGURE 3) J 39919 CONSIST OF: J 39919-1 REAMER AND J 39919-2 GAGE PIN

STEP 1: VISUALLY INSPECT THE THREADS OF THE CENTER SUPPORT FOR DAMAGE AND PROCEED IF THREADS APPEAR OKAY.

STEP 2: WITH THE CENTER SUPPORT REMOVED FROM THE TRANSMISSION, ATTEMPT TO INSERT J 39919-2 GAGE PIN INTO THE CENTER SUPPORT THREADED HOLE (LARGE CHAMFER END TOWARDS HOLE). NOTE: DO NOT FORCE GAGE PIN INTO HOLE.

* IF GAGE PIN WILL NOT FIT INTO HOLE (AT LEAST HALF WAY) PROCEED TO STEP 3.

* IF GAGE PIN FITS INTO HOLE, REPLACEMENT OF THE CENTER SUPPORT IS NECESSARY.

STEP 3: PROCEED WITH THIS STEP ONLY IF GAGE PIN WON'T FIT INTO THREADED HOLE.

* USING J 39910-1 REAMER AND AN APPROPRIATE T-HANDLE, POSITION J 39919-1 INTO HOLE.

* ROTATE J 39919-1 BY HAND IN A CLOCKWISE DIRECTION USING LIGHT PRESSURE. (DO NOT USE A DRILL MOTOR.)

* ROTATE J 39919-1 APPROXIMATELY 4-6 TIMES OR UNTIL REAMER PASSES THROUGH HOLE AND BOTTOMS OUT.

* REMOVE J 39919-1 AND CLEAN CENTER SUPPORT BEFORE ASSEMBLY.

NOTE: THIS TOOL IS DESIGNED TO REMOVE A MINIMAL AMOUNT OF MATERIAL FROM THE HOLE TO INSURE PROPER FIT OF THE NEW RETAINING BOLT.

BEFORE REASSEMBLY INTO THE TRANSMISSION CASE, INSPECT THE CENTER SUPPORT FOR WEAR AND/OR DAMAGE AND FOR PRESENCE OF THE ORIFICE CUP PLUG. CHECK THE CASE FOR ANY ELONGATION OF BOLT THROUGH HOLE OR DAMAGE TO BOLT HEAD SEATING AREA.

FIGURES: 3

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER." THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS OCCURRING 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 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.

COPYRIGHT 1994. GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.