SMU - SECTION 7A - AUTOMATIC TRANSMISSION

SUBJECT: SERVICE MANUAL UPDATE - SECTION 7A - AUTOMATIC TRANSMISSION

MODELS: 1997 CHEVROLET AND GMC C/K TRUCK WITH HYDRA-MATIC 4L80E TRANSMISSION (RPO MT1)

THIS BULLETIN UPDATES THE 1997 C/K TRUCK AUTOMATIC TRANSMISSION 4L80E DIAGNOSIS SECTION. REPLACE THE ATTACHED PAGES IN YOUR SERVICE MANUAL. THE UPDATES ARE AS FOLLOWS:

COMPONENT RESISTANCE CHART CIRCUIT NUMBERS CORRECTED.

AUTOMATIC TRANSMISSION WIRING HARNESS ASSEMBLY 20-WAY CONNECTOR, ENGINE SIDE TERMINALS 'L' AND 'P' WIRE COLORS CORRECTED.

DTC P0730 INCORRECT GEAR RATIO (5.7L AND 7.4L GAS) STEPS 5, 6, 7, 8 AND THE 'VALUES', 'YES', AND 'NO' COLUMNS CORRECTED.

DTC P1871 UNDEFINED GEAR RATIO (6.5L DIESEL ONLY) STEPS 5, 6, 7, 8 AND 9 THE 'VALUES', 'YES', AND 'NO' COLUMNS CORRECTED.

DTC P1875 4 WHEEL DRIVE SWITCH CIRCUIT (6.5L DIESEL) AND (5.7L AND 7.4L GAS) STEPS 2, 3 AND 4 'ACTION' COLUMN CORRECTED.

1-2 SHIFT SOLENOID VALVE AND 2-3 SHIFT SOLENOID VALVE DESCRIPTIONS CORRECTED.

AUTOMATIC TRANSMISSION INPUT SPEED, OUTPUT SPEED SENSORS DESCRIPTIONS CORRECTED.

AUTOMATIC TRANSMISSION FLUID TEMPERATURE SENSOR ASSEMBLY DESCRIPTION CORRECTED.

FIGURES: 0 ATTACHMENTS: 11

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 1996. GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.