For 1990-2009 cars

# REVERSE CLUTCH CHATTER CORRECTION PROCEDURE OUTLINED

SOME 1983 "F" SERIES EQUIPPED WITH THE 2.8L V6 ENGINE (LC1/LL1) AND BORG-WARNER FIVE-SPEED MANUAL TRANSMISSION (MK5) MAY EXHIBIT REVERSE GEAR CLUTCH CHATTER. THIS CAN BE CORRECTED ON MOST VEHICLES BY CHANGING THE CLUTCH CORDON SHAFT GEOMETRY AND INSTALLING A DIFFERENT TRANSMISSION REAR MOUNT. IN SOME INSTANCES, A NEW CLUTCH ASSEMBLY WILL ALSO BE REQUIRED. THE FOLLOWING REPAIR PROCEDURE IS RECOMMENDED: 1. CYCLE CLUTCH SEVERAL TIMES TO NORMALIZE THE LINKAGE; THEN PERFORM THE CLUTCH PEDAL FREE TRAVEL ADJUSTMENT AS OUTLINED IN THE SERVICE MANUAL. 2. MEASURE THE HORIZONTAL DISTANCE BETWEEN THE CLUTCH FORK PUSH ROD'S RETAINER CLIP HOLE AND THE NEAREST POINT ON THE ENGINE'S OIL PAN (SEE ILLUSTRATION). 3. IF MEASUREMENT IS 130MM PLUS 5MM MINUS 0MM (5 1/8" PLUS 3/16" MINUS 0) PROCEED TO STEP 6. IF LESS THAN 130MM, REWORK THE CLUTCH CORDON SHAFT LOWER LEVER TO ACHIEVE THAT VALUE AS FOLLOWS: A. REMOVE THE CORDON SHAFT AND LEVER ASSEMBLY (P/N 14056673) FROM THE VEHICLE. B. CAREFULLY CLAMP THE LOWER LEVER PORTION OF THE ASSEMBLY IN A VISE SUCH THAT THE VISE JAWS ARE CENTRALLY LOCATED BETWEEN THE LEVER'S WELD JOINT ON ONE END, AND ITS EXTRUDED (LOWER) HOLE ON THE OTHER. C. REDUCE THE AMOUNT OF EXISTING BEND IN THE LOWER LEVER BY SLOWLY TIGHTENING THE VISE. AN ENTIRELY STRAIGHTENED LEVER REPRESENTS A 9MM (3/8") CORRECTION. D. IF LEVER REQUIRES MORE THAN A 9MM (3/8") CORRECTION, IT CAN BE FURTHER REWORKED AS FOLLOWS: 1. REPOSITION THE LEVER IN THE VISE TO ALLOW THE JAWS TO CLAMP ON THE FLAT SURFACE AREA ADJACENT TO THE WELD JOINT. 2. CLAMP A LOCKING PLIER ADJACENT TO THE EXTRUDED HOLE AND CONTINUE TO BEND THE LEVER IN THE DIRECTION REQUIRED TO ACHIEVE THE NECESSARY DEFLECTION. CAUTION: RESHAPING OF LEVER MUST BE ACCOMPLISHED WITHOUT RESULTING IN A BROKEN WELD JOINT. E. INSTALL THE REWORKED CORDON SHAFT AND LEVER ASSEMBLY ON THE VEHICLE. 4. CYCLE CLUTCH SEVERAL TIMES TO NORMALIZE THE LINKAGE; THEN READJUST THE CLUTCH PEDAL FREE TRAVEL AS REQUIRED. 5. REMEASURE THE HORIZONTAL DISTANCE BETWEEN THE SAME TWO POINTS AS BEFORE. A MEASUREMENT OF 130MM PLUS 5MM MINUS 0 (5 1/8" PLUS 3/16" MINUS 0) INDICATES PROPER REWORK OF THE LOWER LEVER. 6. REMOVE AND REPLACE THE ORIGINAL PRODUCTION TRANSMISSION REAR MOUNT WITH AN AFTER MARKET MOUNT SIMILAR TO REPUBLIC PARTS, INC, P/N 31-2385 OR DOAN-ANCHOR, INC., P/N 23-37. NOTICE: PRIOR TO INSTALLATION, INSPECT AND REMOVE, IF NECESSARY, ANY RUBBER FLASH MATERIAL FROM THE REPLACEMENT MOUNT'S BOLT CLAMPING SURFACES. 7. IF VEHICLE STILL EXHIBITS CHATTER DURING ROAD TEST, REFER TO THE 1983 "F" SERVICE MANUAL CLUTCH DIAGNOSTIC CHART, FIGURE 7C-4. FOLLOW THE CLUTCH DIAGNOSIS PROCEDURE FOR A GRABBING (CHATTERING) CONDITION. (SEE ILLUSTRATION FOR CORDON SHAFT CLEARANCE DIMENSIONS).

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.