INFO. ON TRANSMISSION PRODUCT UPDATES. GMC Truck Export GMC P42 Commercial Chassis 1998

For 1990-2009 cars

# INFO. ON TRANSMISSION PRODUCT UPDATES

#### SUBJECT: INFORMATION ON TRANSMISSION PRODUCT UPDATES

#### MODELS: 1998 CHEVROLET AND GMC C/K, G, P TRUCKS 1998 AM GENERAL 1998 ISUZU 1998 REUMECH ERMETEK WITH HYDRA-MATIC 4L80E TRANSMISSION (RPO MT1)

THE FOLLOWING PRODUCT UPDATES HAVE BEEN IMPLEMENTED ON THE HYDRA-MATIC 4L80E TRANSMISSION DURING THE 1998 MODEL YEAR AND HAVE AN AFFECT ON SERVICE:

UPDATE DESCRIPTION SEAL MATERIAL IMPROVEMENT (FIGURE 1)

THE DIRECT CLUTCH HOUSING OIL SEAL RING (639) AND THE OVERRUN CLUTCH HOUSING OIL SEAL RING (219) MATERIAL IS NOW A "PEEK" SEAL RING MATERIAL WITH A DOUBLE STEP JOINT DESIGN.

TORQUE CONVERTER BUSHING IMPROVEMENT (FIGURE 2)

THE TORQUE CONVERTER BUSHING (202) IS 0.140 INCH LONGER AND THE OIL PUMP BODY CASTING (203) WAS MODIFIED TO ACCOMMODATE THE NEW BUSHING.

UPDATE IDENTIFICATION THIS PRODUCT UPDATE WAS IMPLEMENTED IN PRODUCTION ON ALL 1998 4L80E MODELS S.O.P.

AFFECT ON SERVICE

THE DIRECT CLUTCH HOUSING OIL SEAL RING AND THE OVERRUN CLUTCH HOUSING OIL SEAL RING WILL NOT SERVICE PAST MODEL YEAR 4L80E TRANSMISSIONS.

THE INSTALLATION AND SIZING TOOLS ARE NO LONGER REQUIRED TO INSTALL THESE OIL SEALS. BE CAREFUL NOT TO OVER EXPAND THE OIL SEAL RING DURING INSTALLATION.

THE OIL PUMP BODY ASSEMBLY WILL SERVICE ALL MODEL YEAR OIL PUMP COVERS.

FIGURES: 02 ATTACHMENTS: 00

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.

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