EARLY FRONT AXLE FRONT WHEEL DRIVE SHAFT SEAL WEAR-OUT

REVISION: 06/08/95

THIS BULLETIN IS BEING REVISED TO GIVE SPECIAL INSTRUCTIONS TO ALL GM OF CANADA DEALERS. ----------------------------------------------------------------------

REVISION: 12/01/95

THIS BULLETIN IS BEING REVISED TO CORRECT THE "MODELS" INVOLVED INFO. PLEASE DISCARD BULLETIN 56-33-01 (SECTION 3 - STEERING/SUSPENSION). **********************************************************************

SUBJECT: EARLY FRONT AXLE FRONT WHEEL DRIVE SHAFT SEAL WEAR-OUT (REPLACE LOWER CONTROL ARM OR INSTALL SEAL COVER)

MODELS: 1988-95 CHEVROLET AND GMC TRUCK K MODELS PLANT CODES Z,1,E BUILT PRIOR TO THE FOLLOWING VIN BREAKPOINTS: 1995 CHEVROLET AND GMC TRUCK K MODELS PLANT CODE J, BUILT PRIOR TO THE FOLLOWING VIN BREAKPOINTS:

PLANT DIVISION VIN FT. WAYNE CHEVROLET 1GCEK14H6SZ129588 1995 JANESVILLE CHEVROLET 1GNFK16K1SJ339633 OSHAWA CHEVROLET 2GBEK19K0S1131421 PONTIAC CHEVROLET 1GCEK19KXSE129802 FT WAYNE GMC TRUCK 1GTEK14ZXSZ510515 1995 JANESVILLE GMC TRUCK 1GKFK16K7SJ720304 OSHAWA GMC TRUCK 2GTEK19K7S1514011 PONTIAC GMC TRUCK 1GTEK19KXSE507763

CONDITION:

SOME OWNERS OF VEHICLES WHICH OPERATE PRIMARILY IN OFF- HIGHWAY ENVIRONMENTS MAY COMMENT ON PREMATURE WEAR-OUT OF THE FRONT AXLE SEALS (FRONT WHEEL DRIVE SHAFT CV BOOTS).

CAUSE:

OFF-HIGHWAY USAGE CAN RESULT IN THE BUILD-UP OF DEBRIS (MUD, ICE, ETC.) ON THE LOWER CONTROL ARM. IF THE AMOUNT OF DEBRIS IS EXCESSIVE, CONTACT WITH THE FRONT AXLE FRONT WHEEL DRIVE SHAFT SEAL MAY RESULT. THE RESULT MAY BE AN EARLY WEAR-OUT OF THE SEAL.

CORRECTION:

IMPORTANT: IMPLEMENTATION OF THIS BULLETIN BY CANADIAN DEALERS ON VEHICLES WITHIN WARRANTY PERIOD REQUIRES PRIOR DSM APPROVAL.

K - MODELS WITH 8600# GVW'S AND BELOW:

FOR K TRUCKS WITH 8600# GVW'S AND BELOW, A NEW LOWER CONTROL ARM IS AVAILABLE FEATURING AN OPENING UNDER THE FRONT AXLE OUTBOARD BOOT (FIGURE 1). THE OPENING SHOULD PREVENT THE BUILD-UP OF DEBRIS BY ALLOWING THE DEBRIS TO FALL THROUGH.

THE NEW LOWER CONTROL ARM WENT INTO PRODUCTION AFTER THE BEGINNING OF THE 1995 MODEL YEAR STARTING WITH THE VIN BREAKPOINTS LISTED ABOVE.

ADDITIONALLY, FOR VEHICLES OPERATING IN SEVERE USAGE ENVIRONMENTS (SNOW PLOWS, MINES, ETC.) A FRONT AXLE SEAL COVER IS AVAILABLE AND CAN BE USED IN CONJUNCTION WITH THE NEW LOWER CONTROL ARM (FIGURE 2). THE PURPOSE OF THIS PROTECTIVE DEVICE IS TO SWEEP AS MUCH DEBRIS AS POSSIBLE FROM THE LOWER CONTROL ARM. THIS SHOULD EXTEND THE LIFE OF THE FRONT AXLE SEAL.

IT SHOULD BE NOTED HOWEVER THAT THE PROTECTIVE SEAL COVER WILL, DURING ITS USEFUL LIFE, TAKE ON A RAGGED APPEARANCE WHILE STILL ADEQUATELY PROTECTING THE DRIVE AXLE SEAL. THE DEVICE IS FUNCTIONING AS LONG AS THE FABRIC CONTINUES TO SWEEP DEBRIS FROM THE LOWER CONTROL ARM.

K - MODELS WITH GVW'S ABOVE 8600#

FOR K-MODELS WITH GVW'S ABOVE 8600# A FRONT AXLE SEAL COVER IS AVAILABLE (FIGURE 2). THE PURPOSE OF THIS PROTECTIVE DEVICE IS TO SWEEP AS MUCH DEBRIS AS POSSIBLE FROM THE LOWER CONTROL ARM. THIS SHOULD EXTEND THE LIFE OF THE FRONT AXLE SEAL.

IT SHOULD BE NOTED HOWEVER THAT THE PROTECTIVE SEAL COVER WILL DURING ITS USEFUL LIFE, TAKE ON A RAGGED APPEARANCE WHILE STILL ADEQUATELY PROTECTING THE DRIVE AXLE SEAL. THE DEVICE IS FUNCTIONING AS LONG AS THE FABRIC CONTINUES TO SWEEP DEBRIS FROM THE LOWER CONTROL ARM.

LOWER CONTROL ARM REPLACEMENT PROCEDURE: (K-TRUCKS WITH 8600# GVW'S AND BELOW)

FOLLOWING THE PROCEDURE GIVEN IN SECTION 3C OF THE SERVICE MANUAL, REPLACE THE LOWER CONTROL ARMS WITH THE NEW STYLE LOWER CONTROL ARMS. IT SHOULD BE NOTED THAT THE NEW LOWER CONTROL ARMS INCLUDE A PRESSED IN BALL JOINT. PART NUMBERS FOR THE LOWER CONTROL ARM FRONT AND REAR BUSHINGS ARE ALSO GIVEN BELOW.

FRONT AXLE SEAL COVER INSTALLATION PROCEDURE:

FOLLOW THE INSTRUCTIONS INCLUDED IN THE SEAL COVER SERVICE KITS. APPROPRIATE PART NUMBERS ARE SHOWN BELOW.

BE SURE TO ORDER THE CORRECT SEAL COVER BASED ON THE GVW OF THE SUBJECT VEHICLE.

PARTS INFORMATION

P/N DESCRIPTION QTY

12383404 LOWER CONTROL ARM ASSEMBLY (RH) 1 (K -TRUCKS W/ 8600# GVW'S AND BELOW) 12383403 LOWER CONTROL ARM ASSEMBLY (LH) 1 (K -TRUCKS W/ 8600# GVW'S AND BELOW) 15684067 LOWER CONTROL ARM FRT BUSHING 2 15684068 LOWER CONTROL ARM REAR BUSHING 2 12337997 COTTER PIN 2 26039449 FRONT WHEEL DRIVE SHAFT SEAL COVER SERVICE KIT 2 FOR K-TRUCKS WITH 8600# GVW'S AND ABOVE. 26039455 FRONT WHEEL DRIVE SHAFT SEAL COVER SERVICE KIT 2 FOR K-TRUCKS WITH 7200# GVW'S AND BELOW.

PARTS ARE EXPECTED TO BE AVAILABLE FROM GMSPO ON 5/15/95.

WARRANTY INFORMATION

IMPORTANT: IMPLEMENTATION OF THIS BULLETIN BY CANADIAN DEALERS REQUIRES PRIOR DSM APPROVAL. INSTALLATION OF SEAL COVER SERVICE KITS IS AN 'OWNER PAY' SERVICE AND AS SUCH REQUIRES PRIOR OWNER APPROVAL.

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OP DESCRIPTION LABOR TIME E3537 BOTH LOWER CONTROL ARMS REPLACE USE PUBLISHED F1507 BOTH AXLE ASSEMBLIES REMOVE/REPLACE LABOR OPERATION TIME

FIGURES: 2

CAPTIONS: FIGURE 1 - NEW LOWER CONTROL ARM (K-MODELS WITH 8600# GVW'S AND BELOW) 1. LOWER CONTROL ARM 2. OPENING UNDER FRONT AXLE OUTBOARD SEAL

FIGURE 2 - FRONT AXLE SEAL COVER 1. SEAL COVER 2. NYLON STRAP

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.

COPYRIGHT 1995 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.