TRANSMISSION EXTENSION SEAL LEAKS

SUBJECT: TRANSMISSION EXTENSION SEAL LEAKS (INSTALL REVISED SEAL)

MODELS: 1988-94 CHEVROLET AND GMC TRUCK C1-2, G, S, M MODELS WITH 4L60 (MD8) OR 4L60-E (M30) AND ONE PIECE PROPELLER SHAFT

CONDITION:

SOME VEHICLES MAY EXPERIENCE A LEAK FROM THE TRANSMISSION EXTENSION SEAL.

CAUSE:

THIS LEAK MAY OCCUR IF THE SEAL LIPS ARE DAMAGED BY A CORRODED SLIP YOKE BARREL. AS THE REAR SUSPENSION MOVES, THE SLIP YOKE SLIDES PAST THE SEAL LIPS. IF THE SLIP YOKE BARREL IS CORRODED, SEAL DAMAGE CAN OCCUR RESULTING IN A LEAK.

CORRECTION:

INSTALL A REVISED SEAL P/N 24201470. THE SEAL FEATURES A FLEXIBLE BOOT WHICH COVERS THE SLIP YOKE BARREL TO PREVENT CORROSION. THIS SEAL IS USED IN PRODUCTION STARTING WITH THE 1995 MODEL YEAR.

SERVICE PROCEDURE

REFER TO THE APPROPRIATE YEAR AND MODEL LIGHT TRUCK SERVICE MANUAL, SECTION 7A - AUTOMATIC TRANSMISSION ON VEHICLE SERVICE FOR CORRECT SEAL REPLACEMENT PROCEDURE.

IMPORTANT: THIS SEAL HAS A SMALL VENT HOLE IN THE FLEXIBLE BOOT. THIS HOLE MUST BE INSTALLED FACING DOWN OR THE BOOT COULD COLLECT AND HOLD WATER. USE SANDPAPER OR CROCUS CLOTH TO CLEAN ANY RUST OR CORROSION OFF THE SLIP YOKE BARREL BEFORE INSTALLATION. IF THE SLIP YOKE BARREL IS NOT CLEAN, THE SEAL COULD BE DAMAGED.

SERVICE PARTS INFORMATION

P/N DESCRIPTION QTY 24201470 SEAL, TRANS EXTENSION OIL 1

PARTS ARE EXPECTED TO BE AVAILABLE FROM GMSPO ON 12/5/94.

WARRANTY INFORMATION

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OP DESCRIPTION LABOR TIME K6360 SEAL, EXTENSION HOUSING REAR - REPLACE USE PUBLISHED LABOR OPERATION TIME

FIGURES: 1

CAPTIONS: FIGURE 1 - "BOOTED" SEAL

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 1994 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.