INFO ON JATCO ELEC. (R) TRANS. BRAKE BAND. Chevrolet Chevy MD Steel Tilt 67.2" 1991

SUBJECT: INFORMATION ON JATCO ELECTROMATIC (R) TRANSMISSION BRAKE BAND SERVO PISTON STEM REPLACEMENT

MODELS: 1988-97 CHEVROLET TILTMASTER AND GMC FORWARD W4 MODELS WITH JATCO ELECTROMATIC (R) TRANSMISSION

WHEN TRANSMISSION SERVICING REQUIRES REPLACEMENT OF THE BRAKE BAND SERVO PISTON STEM, BE SURE TO ORDER THE CORRECT BRAKE BAND SERVO PISTON STEM FOR THE APPLICABLE BRAKE BAND SERVO PISTON.

1988 - 95 MODELS USE A BRAKE BAND SERVO PISTON P/N 97173585 THAT IS DESIGNED TO WORK ONLY WITH BRAKE BAND SERVO PISTON P/N 94483458. 1995.5 AND LATER MODELS USE A BRAKE BAND SERVO PISTON STEM P/N 97173640 THAT IS DESIGNED FOR USE WITH BRAKE BAND SERVO PISTON P/N 97135607. BOTH BRAKE BAND SERVO PISTON STEMS HAVE THE SAME OVERALL LENGTH, BUT DIFFER IN THEIR SHOULDER LENGTHS. THE BRAKE BAND SERVO PISTON STEM FOR 1995.5 AND LATER MODELS HAS A SHOULDER LENGTH OF 66 MM (2.6IN). THE BRAKE BAND SERVO PISTON STEM FOR 1988 - 95 MODELS HAS A SHOULDER LENGTH OF 55.6 MM (2.2IN). DO NOT USE THE 1995.5 - ON, BRAKE BAND SERVO PISTON STEM WITH THE 1988 - 95 BRAKE BAND SERVO PISTON. IF USED, THE BRAKE BAND SERVO PISTON WILL NOT FIT PROPERLY INTO THE TRANSMISSION CASE DURING REASSEMBLY DUE TO ITS LONGER SHOULDER LENGTH.

PARTS INFORMATION

P/N DESCRIPTION QTY 97173640 STEM; PISTON, BRAKE (1995.5 - ON) 1 (BRAKE BAND SERVO PISTON STEM) 97173585 STEM; PISTON, BRAKE (1988 - 95) 1 (BRAKE BAND SERVO PISTON STEM) 97135607 PISTON; BRAKE BAND SERVO (1995.5 - ON) 1 (BRAKE BAND SERVO PISTON) 94483458 PISTON; BRAKE BAND SERVO (1988 - 95) 1 (BRAKE BAND SERVO PISTON)

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO

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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.