CAMPAIGN:EXHAUST PIPE FLANGE TO MUFFLER CRACKING. GMC Truck GMC MD Steel Tilt 67.2" 1992

GMC NUMBER: 93-C-23 GROUP: 6F ENGINE EXHAUST DATE: MARCH 1994

SUBJECT: EXHAUST PIPE FLANGE TO MUFFLER CRACKING

MODELS: 1991-1993 GMC FORWARD AND CHEVROLET TILTMASTER W4 SERIES WITH AUTOMATIC TRANSMISSIONS

CERTAIN 1991-93 GMC FORWARD AND CHEVROLET TILTMASTER W4 SERIES MAY HAVE AN EXHAUST PIPE THAT COULD FRACTURE. THE EXHAUST PIPE COULD FRACTURE IN FRONT OF THE MUFFLER AS A RESULT OF STATIC LOADING DURING ENGINE IDLE AND DYNAMIC LOADING FROM CHASSIS INPUTS.

TO CORRECT THIS CONDITION, DEALERS WILL INSTALL AN EXHAUST BRACE REPAIR KIT ON 1991 VEHICLES THAT HAVE NOT HAD THIS DONE AND ON 1991-93 VEHICLES, DEALERS WILL INSTALL A NEW RUBBER SUPPORT- BRACKET MOUNTING.

VEHICLES INVOLVED

INVOLVED ARE CERTAIN 1991-93 GMC FORWARD AND CHEVROLET TILTMASTER W4 SERIES BUILT WITHIN THE FOLLOWING VIN BREAKPOINTS:

YEAR MODEL FROM THROUGH 1991 W-4 SOP EOP 1992-93 W-4 SOP EOP

ONLY MODELS EQUIPPED WITH AUTOMATIC TRANSMISSIONS ARE AFFECTED.

THE SPECIFIC VEHICLES INVOLVED IN THIS CAMPAIGN HAVE BEEN IDENTIFIED BY VEHICLE IDENTIFICATION NUMBER COMPUTER LISTINGS. THESE LISTINGS ARE FURNISHED TO ALL INVOLVED DEALERS WITH THE CAMPAIGN BULLETIN. DEALERS SHOULD CONFIRM VEHICLE ELIGIBILITY THROUGH VISS (VEHICLE INFORMATION SERVICE SYSTEM) OR SERVICENET PRIOR TO BEGINNING CAMPAIGN REPAIRS.

DEALER CAMPAIGN RESPONSIBILITY

ALL UNSOLD VEHICLES IN DEALERS' POSSESSION AND SUBJECT TO THIS CAMPAIGN MUST BE HELD AND INSPECTED/REPAIRED PER THE SERVICE PROCEDURE OF THIS CAMPAIGN BULLETIN BEFORE OWNERS TAKE POSSESSION OF THESE VEHICLES.

DEALERS ARE TO SERVICE ALL VEHICLES SUBJECT TO THIS CAMPAIGN AT NO CHARGE TO OWNERS, REGARDLESS OF MILEAGE, AGE OF VEHICLE, OR OWNERSHIP, FROM THIS TIME FORWARD. OWNERS OF VEHICLES RECENTLY SOLD FROM YOUR VEHICLE INVENTORY ARE TO BE CONTACTED BY THE DEALER AND ARRANGEMENTS MADE TO MAKE THE REQUIRED CORRECTION ACCORDING TO INSTRUCTIONS CONTAINED IN THIS BULLETIN.

IN SUMMARY, WHENEVER A VEHICLE SUBJECT TO THIS CAMPAIGN ENTERS YOUR VEHICLE INVENTORY, OR IS IN YOUR DEALERSHIP FOR SERVICE IN THE FUTURE, PLEASE TAKE THE STEPS NECESSARY TO BE SURE THE CAMPAIGN CORRECTION HAS BEEN MADE BEFORE SELLING OR RELEASING THE VEHICLE.

IF THE NAME AND ADDRESS OF THE OWNER OF AN INVOLVED VEHICLE WAS UNAVAILABLE TO GMC TRUCK DIVISION AT THE TIME OF CAMPAIGN INITIATION, THE DEALER MUST DETERMINE THE OWNER'S NAME AND ADDRESS FROM THE DEALERSHIP SALES RECORDS. PLEASE PROVIDE THIS INFORMATION DIRECTLY ON THE SECOND COPY OF THE LISTING NEXT TO THE APPLICABLE VIN SO THAT OUR RECORDS MAY BE UPDATED AND THE APPROPRIATE NOTIFICATION MAILED TO THE OWNER. THIS SECOND COPY SHOULD THEN BE SUBMITTED TO THE ADDRESS LISTED BELOW IN THE PREVIOUSLY SUPPLIED YELLOW CAMPAIGN ENVELOPES.

GMC TRUCK DIVISION GENERAL MOTORS CORPORATION 101 UNION STREET PLYMOUTH, MICHIGAN 48170

OWNER NOTIFICATION

OWNERS WILL BE NOTIFIED OF THIS CAMPAIGN ON THEIR VEHICLES BY GMC TRUCK DIVISION (SEE COPY OF OWNER LETTER INCLUDED WITH THIS BULLETIN). A LISTING OF OWNER NAMES AND ADDRESSES HAS BEEN FURNISHED TO THE INVOLVED DEALERS TO ENABLE DEALERS TO FOLLOW UP WITH OWNERS INVOLVED IN THIS CAMPAIGN. THIS LISTING MAY CONTAIN OWNER NAMES AND ADDRESSES OBTAINED FROM STATE MOTOR VEHICLE REGISTRATION RECORDS. THE USE OF SUCH MOTOR VEHICLE REGISTRATION DATA FOR ANY OTHER PURPOSE IS A VIOLATION OF LAW IN SEVERAL STATES. ACCORDINGLY, YOU ARE URGED TO LIMIT THE USE OF THIS LISTING TO THIS CAMPAIGN.

SERVICE INFORMATION

ON 1991 W4 MODELS ONLY, THE SHIM AND BRACKET MODIFICATION DESCRIBED IN PROCEDURE I MAY HAVE ALREADY BEEN DONE PER TSB 91-6F- 102 OR IT MAY NOT HAVE BEEN DONE. IF THE SHIM AND BRACKET MODIFICATION HAS NOT BEEN DONE, PLEASE COMPLETE THE MODIFICATION AT THIS TIME USING REPAIR KIT NUMBER 97047012 OR 97061375 DEPENDING ON MODEL. HOWEVER, THESE KITS CONTAIN AN INCORRECT RUBBER MOUNT BRACKET, YOU MUST REPLACE THE RUBBER MOUNT BRACKET IN THESE KITS WITH THE NEW PART NUMBER 97101823 RUBBER MOUNT BRACKET FOLLOWING PROCEDURE II. IMPORTANT: PROCEDURE I IS TO BE PERFORMED ON 1991 W4 MODELS ONLY IF THE SHIM AND BRACKET MODIFICATION DESCRIBED HAVE NOT PREVIOUSLY BEEN DONE PER TSB 91-6F-102. IF THE MODIFICATION HAS BEEN COMPLETED PREVIOUSLY, THEN REPLACE THE EXISTING INSTALLED RUBBER MOUNT BRACKET WITH NEW PART NUMBER 97101823 RUBBER MOUNT BRACKET FOLLOWING PROCEDURE II.

PROCEDURE II IS ALSO FOR 1992-93 MODELS WHICH WERE BUILT WITH THE SHIM AND BRACKET MODIFICATION. HOWEVER, ON THESE UNITS, THE RUBBER MOUNT BRACKET NEEDS TO BE REPLACED WITH NEW PART NUMBER 97101823 RUBBER MOUNT BRACKET.

SERVICE PROCEDURE

REFER TO FIGURES 1, 2, 3, AND 4.

PROCEDURE I

1.DISCONNECT BATTERY AND CHOCK WHEELS.

2.INSTALL EXHAUST BRACE BRACKET (1) TO FRAME RAIL ON PRE-DRILLED HOLES AND TORQUE BOLTS TO 17 N M (13 LBS. FT.) (FIGURES 1 AND 2).

3.INSTALL MOUNTING RUBBER (2) TO EXHAUST BRACE BRACKET (1) AND TORQUE BOLT TO 13 N M (10 LBS. FT.) (FIGURES 1 AND 4).

4.INSTALL THE TWO-PIECE EXHAUST PIPE BRACKET (3) AND (4) LOOSELY ASSEMBLE, MAKING SURE THE HEAT SHIELD IS DIRECTLY UNDER THE MOUNTING RUBBER (2) AND IS FACING THE REAR OF THE VEHICLE (FIGURES 1 AND 4).

5.INSTALL THE NUT AND FLAT WASHER TO JOIN THE EXHAUST PIPE BRACKET (3) AND (4) TO THE MOUNTING RUBBER (2) AND TORQUE NUT TO 13 N M (10 LBS. FT.) (FIGURE 1).

6.TORQUE THE EXHAUST PIPE BRACKET (3) AND (4) BOLTS TO 13 N M (10 LBS. FT.) (FIGURE 1).

7.LOOSEN THE TWO NUTS OFF THE MUFFLER FLANGE STUDS, THEN INSTALL THE TWO SHIMS (5) TO EACH SIDE OF THE STUDS BETWEEN FLANGES (FIGURE 1 AND 3). TORQUE NUTS TO 37 N M (27 LBS. FT.).

8.RECONNECT THE BATTERY AND UNCHOCK THE WHEELS.

PROCEDURE II

1.DISCONNECT BATTERY AND CHOCK WHEELS.

2.LOOSEN AND REMOVE THE NUT, WASHER AND BOLT FROM THE MOUNTING RUBBER (2) AND THE BRACE BRACKET (1), LOOSEN AND REMOVE NUT AND WASHER FROM STUD ON MOUNTING RUBBER (2)AND EXHAUST PIPE BRACKET (3-4) (FIGURE 4).

3.REMOVE OLD MOUNTING RUBBER (2).(FIGURE 4).

4.INSTALL NEW MOUNTING RUBBER (2) WHICH HOLDS EXHAUST PIPE BRACKET (3-4) (FIGURE 4).

5.TORQUE BOLTS TO 17 N M (13 LBS. FT.).

6.RE-CONNECT BATTERY AND UNCHOCK THE WHEELS

PARTS INFORMATION

PARTS ARE TO BE OBTAINED DIRECTLY FROM AMERICAN ISUZU PARTS DISTRIBUTION NETWORK (A.I.P.D.N.).

PART NUMBER DESCRIPTION QUANTITY 97047012 KIT, REPAIR, EXHAUST 1 KIT BRACE 1991(ONLY) W4 OR W4- FL 97061375 KIT., REPAIR, 1 KIT EXHAUST BRACE, 1991(ONLY) W4-ST 97101823 MOUNTING, RUBBER, 1 EXHAUST PIPE, 1991- 93

WARRANTY INFORMATION

DEALERS SHOULD SUBMIT A WARRANTY CLAIM ON EACH VEHICLE COMPLETED UNDER THIS CAMPAIGN.

LABOR OPERATION *TIME PARTS TROUBLE NUMBER DESCRIPTION ALLOWANCE ALLOWANCE CODE INSTALL REPAIR V 8790 KIT .2 $13.53** 96 97047012 (1991 ONLY) INSTALL REPAIR V 8791 KIT 97061375 .2 $18.59** 96 (1991 ONLY)

V 8792 INSTALL RUBBER .2 $1.64** 96 MOUNT (1991-93)

* FOR DEALER TO RECEIVE ADMINISTRATIVE TIME ALLOWANCE ASSOCIATED WITH THIS CAMPAIGN, ADD 0.1 HOUR TO THE LABOR OPERATION TIME ALLOWANCE.

** THE AMOUNT IDENTIFIED IN THE "PARTS ALLOWANCE" COLUMN ABOVE REPRESENTS 30% OF DEALER NET FOR PARTS THAT ARE FURNISHED IN THIS CAMPAIGN. THIS AMOUNT IS TO BE PLACED IN THE NET ITEM AMOUNT COLUMN OF THE CLAIM AND TYPE CODE "M."

CAMPAIGN IDENTIFICATION LABEL

EACH VEHICLE CORRECTED IN ACCORDANCE WITH THE INSTRUCTIONS OUTLINED IN THIS PRODUCT CAMPAIGN BULLETIN WILL REQUIRE A "CAMPAIGN IDENTIFICATION LABEL." EACH LABEL PROVIDES A SPACE TO INCLUDE THE CAMPAIGN NUMBER AND FIVE (5) DIGIT DEALER CODE OF THE DEALER PERFORMING THE CAMPAIGN SERVICE. THIS INFORMATION MAY BE INSERTED WITH A TYPEWRITER OR BALL POINT PEN.

EACH "CAMPAIGN IDENTIFICATION LABEL" IS TO BE LOCATED ON THE RADIATOR CORE SUPPORT IN AN AREA WHICH WILL BE VISIBLE WHEN THE VEHICLE IS BROUGHT IN FOR PERIODIC SERVICING BY THE OWNER.

APPLY "CAMPAIGN IDENTIFICATION LABEL" ONLY ON A CLEAN, DRY SURFACE.

ADMINISTRATIVE PROCEDURE

PROCEDURES COVERING THIS CAMPAIGN ARE OUTLINED IN SECTION V OF YOUR DEALERSHIP'S "GMC TRUCK WARRANTY CLAIMS PROCESSING MANUAL" #P9119.

FIGURES: 4

GMC TRUCK BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THESE 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 YOUR GMC TRUCK DEALER FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.

DEAR GM TRUCK OWNER:

AS A VALUED CUSTOMER, YOUR COMPLETE SATISFACTION WITH YOUR GM TRUCK IS OUR GOAL. IN KEEPING WITH THIS GOAL, WE WANT TO LET YOU KNOW THAT WE HAVE DISCOVERED A PROBLEM THAT COULD AFFECT YOUR VEHICLE.

INSTRUCTIONS FOR PERFORMING THIS SERVICE HAVE BEEN SENT TO YOUR GM MEDIUM DUTY DEALER, AND PARTS ARE AVAILABLE. PLEASE CONTACT YOUR GM MEDIUM DUTY DEALER TO ARRANGE A SERVICE DATE AS SOON AS POSSIBLE. THIS PROCEDURE WILL TAKE ABOUT 12 MINUTES TO COMPLETE, BUT YOU SHOULD ASK HOW MUCH ADDITIONAL TIME YOUR DEALER WILL NEED TO SCHEDULE AND PROCESS YOUR VEHICLE.

THE ENCLOSED POSTAGE PAID OWNER REPLY CARD IDENTIFIES YOUR VEHICLE. PRESENTATION OF THIS CARD TO YOUR DEALER WILL ASSIST IN MAKING THE NECESSARY CORRECTION TO YOUR VEHICLE IN THE SHORTEST POSSIBLE TIME. IF YOU HAVE SOLD OR TRADED YOUR VEHICLE, PLEASE FURNISH US THE COMPLETE NAME AND ADDRESS OF THE PERSON YOU SOLD OR TRADED YOUR VEHICLE TO AND RETURN THE CARD TO US.

WE ARE SORRY TO CAUSE YOU THIS INCONVENIENCE; HOWEVER, WE HAVE TAKEN THIS ACTION IN THE INTEREST OF YOUR CONTINUED SATISFACTION WITH OUR PRODUCT.

GMC TRUCK DIVISION GENERAL MOTORS CORPORATION

93C23 ENCLOSURE