TRANS. SLIPS IN OVERDRIVE (INSTALL NEW BAND SERVO BOLTS)

SUBJECT: TRANSMISSION SLIPS IN OVERDRIVE (INSTALL NEW BAND SERVO RETAINER BOLTS)

MODELS: 1992-93 CHEVROLET AND GMC TRUCK W4 MODELS WITH DIESEL ENGINES AND JATCO ELECTROMATIC TRANSMISSIONS

CONDITION:

SOME OWNERS MAY EXPERIENCE A SLIPPING CONDITION IN OVERDRIVE (FOURTH GEAR).

CAUSE:

THIS CONDITION MAY BE CAUSED BY FRACTURED BAND SERVO RETAINING BOLTS. FRACTURED RETAINING BOLTS CAN CAUSE INTERNAL LEAKAGE OF THE BAND SERVO CIRCUIT WHICH COULD RESULT IN INSUFFICIENT ENGAGEMENT OF THE BRAKE BAND (FIGURE 1).

CORRECTION:

INSTALL NEW BAND SERVO RETAINING BOLTS AND GASKET, TORQUING BOLTS TO 8 N.M (5 LBS. FT.).

SERVICE PROCEDURE:

1. DRAIN TRANSMISSION FLUID. 2. REMOVE OIL PAN FIXING BOLTS AND OIL PAN. 3. LOCATE BAND SERVO RETAINER (FIGURE 2). 4. LOOSEN AND REMOVE FOUR BOLTS FROM BAND SERVO RETAINER (FIGURE 2). 5. REMOVE GASKET.

IMPORTANT: REPLACING THE FOUR RING SEALS ON BAND SERVO PISTON IS RECOMMENDED WHEN BAND SERVO RETAINER IS REMOVED. (SEE SERVICE MANUAL, SECTION 7A4-81 TO 7A4-83.)

6. REPLACE RETAINER GASKET. 7. INSTALL BAND SERVO RETAINER AND FOUR NEW BOLTS. 8. TORQUE FOUR NEW BOLTS TO 8 N.M (5 LBS. FT.). 9. INSTALL OIL PAN TO THE TRANSMISSION CASE. TORQUE OIL PAN BOLTS TO 7 N.M (5 LBS. FT.). 10. REFILL TRANSMISSION WITH DEXRON-IIE FLUID.

SERVICE PARTS INFORMATION:

P/N DESCRIPTION QTY

94483471 RETAINER BOLT 4 94483470 RETAINER GASKET 1

PARTS MAY BE OBTAINED DIRECTLY FROM AMERICAN ISUZU PARTS DISTRIBUTION NETWORK (A.I.P.D.N.).

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OP DESCRIPTION LABOR TIME K6620 SERVO ASSEMBLY, INTERMEDIATE - USE PUBLISHED REMOVE AND REPLACE LABOR OPERATION TIME

FIGURES: 2

CAPTIONS: FIGURE 1 - BAND SERVO CIRCUIT FIGURE 2 - BAND SERVO RETAINER BOLTS (4)

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.