SMU - SECTION 7B - M/T SPEEDOMETER DRIVEN GEAR. Chevrolet Chevy MD Steel Tilt 67.2" 1991

SUBJECT: SERVICE MANUAL UPDATE - SECTION 7B - MANUAL TRANSMISSION - SPEEDOMETER DRIVEN GEAR BACKLASH PROCEDURE/SPECIFICATIONS

MODELS: 1990-92 W5, W6 AND W7 WITH FIVE AND SIX SPEED MANUAL TRANSMISSIONS (RPOS MBG AND MLD)

1990-92 SERVICE MANUALS DO NOT CONTAIN THE FOLLOWING SPEEDOMETER DRIVEN GEAR BACKLASH ADJUSTMENT PROCEDURES. THE FACTORY REPLACEMENT PART DOES NOT HAVE THE SET SCREW POSITIONING HOLE. THE GEAR BUSHING SET SCREW HOLE MUST BE DRILLED WHEN REPLACING THE SPEEDOMETER GEAR BUSHING.

SERVICE PROCEDURE:

THE FOLLOWING PROCEDURE IS FROM 1993 AND AFTER W5, W6 AND W7 SERVICE MANUALS.

1. INSTALL THE DRIVEN GEAR AND BUSHING IN THE REAR COVER (FIG. 1). 2. ROTATE THE BUSHING TOWARD VEHICLE FRONT UNTIL THERE IS NO BACKLASH BETWEEN THE DRIVEN GEAR AND DRIVE GEAR. 3. MARK THE BUSHING AND THE REAR COVER (FIG. 1). 4. ROTATE THE BUSHING IN THE REVERSE DIRECTION BY MEASUREMENT "A" AS SPECIFIED IN TABLE 1. THE BACKLASH BETWEEN THE GEARS WILL BE SET IN THE SPECIFIED RANGE 0.1 - 0.3 MM (0.004" - 0.012") AFTER PERFORMING THIS PROCEDURE (FIG. 1 AND TABLE 1). 5. MARK A SET SCREW HOLE BORING POSITION ON THE BUSHING, USING A MARKER PEN THROUGH THE REAR COVER SET SCREW INSTALLING HOLE. 6. REMOVE THE BUSHING AND DRIVEN GEAR FROM THE REAR COVER. THEN MAKE A SET SCREW ACCESS HOLE WITH A DRILL (REFER TO TABLE 2 FOR DIAMETER AND DEPTH OF HOLE). 7. REINSTALL THE DRIVEN GEAR AND BUSHING IN THE REAR COVER. ALIGN THE ACCESS HOLE WITH THE SET SCREW AND TORQUE SCREW TO 3.9 - 7.8 N.M (2.9 - 5.8 LBS. FT.).

TABLE 1

BACKLASH ADJUSTMENT PROCEDURE

FIVE SPEED (MBG)

TEETH ON DRIVEN GEAR/ TEETH ON DRIVE GEAR (A) MM (IN)

14/6 1.7 (0.066) 15/6 1.7 (0.066) 16/6 1.7 (0.066) 17/6 1.7 (0.066) 18/6 1.7 (0.066) 19/6 1.7 (0.066) 20/6 2.4 (0.094) 14/4 1.7 (0.066) 15/4 1.7 (0.066) 16/4 2.0 (0.078)

SIX SPEED (MLD)

TEETH ON DRIVEN GEAR/ TEETH ON DRIVE GEAR (A) MM (IN)

12/7 3.1 (0.122) 13/7 2.2 (0.086) 14/7 2.2 (0.086) 15/7 2.2 (0.086) 16/7 2.2 (0.086) 17/7 2.2 (0.086) 18/7 2.2 (0.086) 19/7 2.2 (0.086) 20/7 3.1 (0.122) 15/5 2.2 (0.086) 16/5 2.2 (0.086) 17/5 2.2 (0.086)

TABLE 2

SET SCREW HOLE SIZE

DIAMETER - MM (IN) DEPTH - MM (IN)

4.5 (0.177) 3.5 - 4.0 (0.138 - 0.157)

FIGURES: 1

CAPTIONS: FIGURE 1 - DRIVEN GEAR AND BUSHING/REAR COVER

Object Number: 94370 Size: MF

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.