SERVICE MANUAL UPDATE-SEC. 7A TRANSMISSION UNIT REPAIR

********************************************************************** TRANSMISSION APPLICATIONS: SUBJECT: 1993 HYDRA-MATIC 4L60 (MD8) SERVICE MANUAL UPDATE--SECTION 7 1993 HYDRA-MATIC 4L60 TRANSMISSION UNIT REPAIR (GENERAL INFORMATION)

TRANSMISSION MODELS: VEHICLE APPLICATIONS: ALL B, D, F, Y-CARS S, T-TRUCKS WITH 2.5L (L38) ENGINE **********************************************************************

BULLETIN COVERS:

NEW PRODUCT INFORMATION FOR 1993 HYDRA-MATIC 4L60 TRANSMISSIONS. THIS INFORMATION HAS BEEN UPDATED SINCE PUBLICATION OF THE 1993 SERVICE MANUAL AND SHOULD BE NOTED ACCORDINGLY. BE CERTAIN TO FAMILIARIZE YOURSELF WITH THESE UPDATES TO PROPERLY REPAIR THE 1993 HYDRA-MATIC 4L60 TRANSMISSION.

DATE OF PRODUCTION CHANGE:

BEGINNING WITH START OF PRODUCTION 1993, HYDRA-MATIC 4L60 TRANSMISSIONS WERE BUILT WITH AN IMPROVED PARK TO REVERSE ENGAGEMENT. AN ADDED CHECK BALL IN THE REVERSE PASSAGE OF THE VALVE BODY (55I) AND NEW SPACER PLATE TO CASE GASKET (ILL. 88) AND A NEW SPACER PLATE TO VALVE BODY GASKET (ILL. 89) WERE ALL NEEDED FOR THIS IMPROVEMENT.

NOTE: IT IS VERY IMPORTANT THAT THE NEW SPACER PLATE GASKETS WITH THE TEAR DROP HOLE ARE USED FOR THE 1993 HYDRA-MATIC 4L60. IF A PREVIOUS GASKET IS USED ON THE 1993 MODELS IT CAN BLOCK THE REVERSE APPLY ORIFICE.

SERVICE MANUAL REFERENCE:

UPDATE YOUR 1993 SERVICE MANUAL WITH THE FOLLOWING SIX (6) PAGES.

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER." THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS OCCURRING 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 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 1993, GM POWERTRAIN DIVISION. GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.