INFORMATION ON NEW 2 -4 BAND ASSEMBLY

SUBJECT: INFORMATION ON NEW 2-4 BAND ASSEMBLY, 3-4 CLUTCH FRICTION AND STEEL PLATES AND TORQUE CLUTCH PWM SOLENOID

MODELS: 1995 BUICK ROADMASTER 1995 CADILLAC FLEETWOOD 1995 CHEVROLET CAMARO, CAPRICE, CORVETTE 1995 PONTIAC FIREBIRD 1995 CHEVROLET AND GMC TRUCK C/K MODELS AND M/L AND G VANS 1994-95 CHEVROLET AND GMC TRUCK S/T MODELS 1994 OLDSMOBILE BRAVADA (1994 MODELS WITH RPO +CTF PACKAGE)

TRANSMISSION APPLICATIONS: 1995 HYDRA-MATIC 4L60-E (RP0 M30)

A NEW 2-4 BAND ASSEMBLY WAS INTRODUCED AT THE START OF PRODUCTION FOR THE 1995 MODEL YEAR AND 1994 BRAVADAS AND S/T TRUCKS. THE 2-4 BAND FRICTION MATERIAL HAS CHANGED APPEARANCE FROM A BROWN MATERIAL TO A GRAY/BLACK MATERIAL. THIS CHANGE WAS MADE TO ENHANCE DURABILITY.

WHEN SERVICING A 1995 HYDRA-MATIC 4L60-E TRANSMISSION, DO NOT ASSUME THAT THE 2-4 BAND IS BURNED/DAMAGED DUE TO ITS DARK COLOR. THIS DARK COLOR IS NORMAL. BEFORE REPLACING THE 2-4 BAND INSPECT IT FOR SCORING, CHUNKING OR HEAVILY WORN FRICTION MATERIAL.

BEFORE REPLACING THE REVERSE INPUT HOUSING AND DRUM ASSEMBLY INSPECT FOR SCORING OR SIGNS OF EXCESSIVE HEAT. THE 2-4 BAND AND/OR REVERSE INPUT HOUSING AND DRUM ASSEMBLY SHOULD BE REPLACED ONLY IF THE ABOVE LISTED DAMAGE IS FOUND.

NOTE: THE NEW 2-4 BAND ASSEMBLY WILL NOT SERVICE PAST MODEL HYDRA-MATIC 4L60-E OR 4L60 TRANSMISSIONS.

A NEW 3-4 CLUTCH FRICTION PLATE WAS INTRODUCED AT THE START OF PRODUCTION FOR THE 1995 MODEL YEAR AND 1994 BRAVADAS AND S/T TRUCKS. THE 3-4 CLUTCH PLATE FRICTION MATERIAL HAS CHANGED APPEARANCE FROM A BROWN MATERIAL TO A GREEN/BLACK MATERIAL. THIS CHANGE WAS MADE TO ENHANCE DURABILITY.

WHEN SERVICING A 1995 HYDRA-MATIC 4L60-E TRANSMISSION, DO NOT ASSUME THAT THE 3-4 CLUTCH FRICTION PLATES ARE BURNED/DAMAGED DUE TO THEIR DARK COLOR. THIS DARK COLOR IS NORMAL. BEFORE REPLACING THE 3-4 CLUTCH FRICTION PLATES INSPECT FOR SCORING, CHUNKING OR HEAVILY WORN FRICTION MATERIAL.

BEFORE REPLACING THE 3-4 CLUTCH STEEL PLATES INSPECT FOR SCORING OR SIGNS OF EXCESSIVE HEAT. THE 3-4 CLUTCH FRICTION PLATES AND/OR 3-4 CLUTCH STEEL PLATES SHOULD BE REPLACED ONLY IF THE ABOVE LISTED DAMAGE IS FOUND.

NOTE: THE NEW 3-4 FRICTION PLATES WILL NOT SERVICE PAST MODEL HYDRA-MATIC 4L60-E OR 4L60 TRANSMISSIONS.

A NEW TORQUE CONVERTER CLUTCH PWM SOLENOID WAS INTRODUCED AT THE START OF PRODUCTION FOR THE 1995 MODEL YEAR AND 1994 BRAVADAS AND S/T TRUCKS. THE NEW TORQUE CONVERTER CLUTCH PWM SOLENOID IS USED TO CONTROL FLUID ACTING ON THE CONVERTER CLUTCH VALVE, WHICH THEN CONTROLS TCC APPLY AND RELEASE. THE SOLENOID IS ATTACHED TO THE CONTROL VALVE BODY ASSEMBLY WITHIN THE TRANSMISSION. THE TCC PWM SOLENOID IS USED TO PROVIDE SMOOTH ENGAGEMENT OF THE TORQUE CONVERTER BY OPERATING ON A NEGATIVE DUTY CYCLE PERCENT OF "ON" TIME.

IF A FAULT IS DETECTED IN THE TCC PWM CIRCUIT, DTC 83 WILL SET.

ATTACHED IS A SERVICE MANUAL UPDATE FOR THE 1-2 AND 3-4 ACCUMULATOR SPRING COLOR CHART. REPLACE THESE PAGES IN YOUR 1995 SERVICE MANUAL.

FIGURES: 0 ATTACHMENTS: 2

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.