CAMPAIGN:WRONG 700R4 TRANS. 6.2L DIESEL 2WD/PREMATURE FAIL

GENERAL MOTORS HAS DETERMINED THAT CERTAIN 1985 C2500 2WD SUBURBAN MODEL TRUCKS EQUIPPED WITH A 6.2L HEAVY DUTY EMISSION DIESEL ENGINE (RPO LL4) AND A 700R4 AUTOMATIC TRANSMISSION (RPO MX0) WERE BUILT WITH THE WRONG TRANSMISSION. OPERATING THE VEHICLE, WITH THIS CONDITION, COULD RESULT IN TORQUE CONVERTOR LUG ATTACHMENT CRACKING AND SUBSEQUENT CONVERTOR LEAKAGE, TORQUE CONVERTOR PUMP VANE FAILURE, TRANSMISSION INTERNAL CLUTCH FAILURES, AND NO UPSHIFT AT WIDE OPEN THROTTLE. IN ADDITION, BECAUSE THE TRANSMISSION WIRING HARNESS IS INCOMPATIBLE WITH THE VEHICLE WIRING HARNESS, THE LOCK UP CLUTCH IN THE TORQUE CONVERTOR WILL NOT ENGAGE RESULTING IN TRANSMISSION OVERHEATING AND SUBSEQUENT PREMATURE FAILURE. TO PREVENT THE POSSIBILITY OF THIS CONDITION OCCURRING, IT WILL BE NECESSARY TO REPLACE THE ORIGINALLY INSTALLED TRANSMISSION ASSEMBLY WITH A CORRECT TRANSMISSION. VEHICLE INVOLVED INVOLVED ARE CERTAIN 1985 C2500 2WD SUBURBAN MODEL TRUCKS EQUIPPED WITH A 6.2L HEAVY DUTY EMISSION DIESEL ENGINE (RPO LL4) AND A 700R4 AUTOMATIC TRANSMISSION (RPO MX0). CHECK THE C.R.I.S. SYSTEM TO DETERMINE IF A SPECIFIC VEHICLE IS INVOLVED IN THIS CAMPAIGN. SERVICE PROCEDURE 1. REMOVE THE ORIGINAL TRANSMISSION ASSEMBLY FROM THE VEHICLE (REFERENCE THE 1984 GMC LIGHT DUTY TRUCK SERVICE MANUAL, X-8432, FOR INSTRUCTIONS). 2. INSTALL REPLACEMENT TRANSMISSION, PART NUMBER 8654525, IN VEHICLE USING SIX NEW TORQUE CONVERTOR ATTACHING BOLTS, PART NUMBER 1261968 (REFERENCE THE 1984 GMC LIGHT DUTY TRUCK SERVICE MANUAL, X-8432, FOR INSTRUCTIONS). 3. REMOVE ALL PLASTIC PLUGS FROM THE REPLACEMENT TRANSMISSION AND INSTALL IN THE REMOVED TRANSMISSION BEING RETURNED. 4. INSTALL ORIGINAL TRANSMISSION DIPSTICK, DIPSTICK TUBE AND THROTTLE VALVE CABLE ON REPLACEMENT TRANSMISSION. 5. ON ALL IN SERVICE MODELS, FLUSH TRANSMISSION COOLER AND LINES (REFERENCE THE 1984 GMC LIGHT DUTY TRUCK SERVICE MANUAL, X-8432, FOR INSTRUCTIONS). 6. ADD TRANSMISSION FLUID TO OBTAIN PROPER LEVEL. 7. INSTALL REPLACEMENT TORQUE CONVERTOR COVER, P/N 14038616, ON REPLACEMENT TRANSMISSION USING FOUR NEW BOLTS, P/N 11500079. 8. ADJUST THE THROTTLE VALVE CABLE PER INSTRUCTIONS CONTAINED IN THE 1984 GMC LIGHT DUTY TRUCK SERVICE MANUAL, X-8432. 9. ROAD TEST VEHICLE TO VERIFY TRANSMISSION PROPER OPERATION AND TORQUE CONVERTOR CLUTCH ENGAGEMENT/DISENGAGEMENT. PARTS INFORMATION PARTS ARE TO BE OBTAINED FROM THE WAREHOUSING AND DISTRIBUTION DIVISION OF GENERAL MOTORS (WDDGM). TO ENSURE THAT THESE PARTS WILL BE OBTAINED AS SOON AS POSSIBLE, THEY SHOULD BE ORDERED FROM WDDGM ON A C.I.O. ORDER WITH NO SPECIAL INSTRUCTION CODE, BUT ORDER UNDER AN ADVISE CODE (2). INVOLVED DEALERS WILL RECEIVE A SHIPPING ID TAG WITH THE CAMPAIGN BULLETIN. TRANSMISSION ASSEMBLIES REMOVED FROM VEHICLES MUST BE TAGGED (SEE SAMPLE BELOW) AND RETURNED IN CONTAINER SUPPLIED WITH REPLACEMENT TRANSMISSION. IF REQUIRED, ADDITIONAL SHIPPING TAGS CAN BE OBTAINED BY CONTACTING YOUR ZONE OFFICE. THE FOLLOWING PARTS ARE REQUIRED FOR EACH VEHICLE INVOLVED: PART NUMBER DESCRIPTION QTY. PER VEHICLE 8654525 TRANSMISSION 1 1051855 FLUID 5 14038616 CONVERTOR COVER 1 11500079 CONVERTOR COVER BOLT 4 1261968 CONVERTOR MTG. BOLT 6 SHIP RETURN TRANSMISSION FREIGHT COLLECT TO THE FOLLOWING ADDRESS CYCLE TEC, 1200 OAKMAN BLVD., DETROIT, MI 48238

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.