440-T4 TRANSMISSION-DEALER AUTHORIZED REPAIR

SINCE THE INTRODUCTION OF THE THM 440-T4 AUTOMATIC TRANSAXLE. SOME UNITS HAVE BEEN REPLACED BY HYDRAMATIC DIVISION THROUGH THE TRANSAXLE EXCHANGE PROGRAM. EFFECTIVE IMMEDIATELY, THE DEALER TECHNICIAN IS TO PERFORM ON-CAR SERVICE TO UNITS THAT MAY EXHIBIT ANY OF THE CONDITIONS LISTED BELOW: - SHIFT CONDITIONS RELATED TO VACUUM - TORQUE CONVERTER CLUTCH DOES NOT RELEASE, CAUSING ENGINE TO STOP RUNNING - UNIT WILL NOT UPSHIFT OR UPSHIFTS LATE - FLUID LEAKS - TORQUE CONVERTER CLUTCH SHUDDER - SLIPS ON UPSHIFT, FREEWHEELS, VIBRATES DURING ACCELERATION - 3-2 DOWNSHIFT, HARSH THESE CONDITIONS ARE TO BE REPAIRED ON-CAR (TRANSAXLE REMOVAL NOT REQUIRED) BY FOLLOWING THE ON-CAR SERVICE INFORMATION CONTAINED HERE AND REFERRING TO SECTION 7-A AND THE 440-T4 UNIT REPAIR PORTION OF THE SERVICE MANUAL. PERFORM ONLY THE SERVICE OPERATIONS SPECIFIED. AT NO TIME SHOULD THE TRANSAXLE CHANNEL PLATE BE REMOVED! IMPORTANT! REPLACEMENT UNITS WILL BE PROVIDED FOR TRANSAXLES THAT EXHIBIT ANY CONDITIONS NOT LISTED IN THIS LETTER. THE FOLLOWING SERVICE INFORMATION IS CONTAINED IN THIS LETTER: A. PRELIMINARY CHECK PROCEDURES. B. DIAGNOSTIC INFORMATION INCLUDING THE FOLLOWING CONDITIONS: 1. VACUUM RELATED SHIFT CONDITIONS. 2. TORQUE CONVERTER CLUTCH WILL NOT RELEASE, CAUSING ENGINE TO STOP RUNNING. 3. TRANSAXLE DOES NOT UPSHIFT OR UPSHIFTS LATE. 4. FLUID LEAKS. 5. TORQUE CONVERTER CLUTCH (T.C.C.) SHUDDER. 6. SLIPS ON UPSHIFTS AND DOWNSHIFTS; FREEWHEELS; VIBRATION ON ACCELERATION. 7. HARSH 3-2 DOWNSHIFT. C. ADDITIONAL ON-CAR SERVICE PROCEDURES BEFORE SERVICING THESE, OR ANY OTHER CONDITIONS, COMPLETE THE FOLLOWING PRELIMINARY CHECK PROCEDURE (SEE FIGURE 1 CHART 1). PRELIMINARY CHECK PROCEDURE CHECK THE TRANSAXLE FLUID TO MAKE SURE THAT IT IS AT THE PROPER LEVEL. NOTE THE FLUID COLOR. BURNED FLUID LOSES ITS RED COLOR AND HAS AN ACRID ODOR. NOTICE: IF THE OIL IS BURNED AND/OR CLUTCH PLATE MATERIAL IS FOUND IN THE OIL PAN, REQUEST A REPLACEMENT TRANSAXLE. - CHECK AND ADJUST T.V. CABLE - CHECK OUTSIDE MANUAL LINKAGE AND CORRECT - CHECK ENGINE TUNE* - INSTALL OIL PRESSURE GAGE** - CONNECT TACHOMETER TO ENGINE - CHECK OIL PRESSURES IN THE FOLLOWING MANNER: MINIMUM LINE PRESSURE CHECK WITH THE PARKING BRAKE SET AND BRAKES APPLIED, TAKE THE LINE PRESSURE READINGS IN THE RANGES AND AT THE ENGINE R.P.M.'S INDICATED IN THE CHART BELOW. FULL LINE PRESSURE CHECK FULL LINE PRESSURE READINGS ARE OBTAINED BY REMOVING THE VACUUM LINE FROM MODULATOR, AND WITH THE PARKING BRAKE SET AND BRAKES APPLIED, TAKE THE LINE PRESSURE READINGS IN THE RANGES AND AT THE ENGINE R.P.M.'S INDICATED IN THE CHART BELOW. NOTE: SEE BULLETIN PUBLICATION REFERENCED FOR CHART SHOWING PRESSURE SPECIFICATIONS. REFER TO THE APPROPRIATE SERVICE MANUAL SECTION FOR COMPLETE PROCEDURES. DO NOT ATTEMPT TO REPAIR POROUS OR CRACKED CASES. - DIAGNOSTIC INFORMATION - BASED ON CONDITION VACUUM RELATED SHIFT CONDITIONS INCLUDE THE FOLLOWING: - HARSH NEUTRAL TO REVERSE - HARSH OR FIRM UPSHIFTS - 2ND GEAR STARTS - HARSH 3-2 COAST-DOWN SHIFTS - ROUGH 4-3 AND 3-2 MANUAL DOWNSHIFTS - SLIPPING IN DRIVE OR REVERSE - ROUGH 1-2 SHIFTS - ERRATIC SHIFTS - HARSH PARK TO REVERSE REFER TO THE FOLLOWING DIAGRAM CHART. SEE BULLETIN PUBLICATION REFERENCED, ALSO SEE BUICK # 85-7440-4. CONDITIONS INSPECTION PROCEDURES TORQUE CONVERTER CLUTCH WILL INSPECT VALVE BODY FOR FOREIGN NOT RELEASE, CAUSES ENGINE TO MATERIAL IN CONVERTER CLUTCH APPLY STOP RUNNING VALVE.

STUCK IN FIRST, NO UPSHIFT; TRANSAXLE NO 2ND GEAR; LATE UPSHIFT WILL NOT UPSHIFT

INSPECT GOVERNOR REPLACE ASSEMBLY FOR DAMAGED AS REQUIRED SPRING, WEIGHTS, OR DEBRIS OR DAMAGED BEARING

IF OK

REMOVE BOTTOM PAN AND CHECK GOV. RETAINER BOLT TORQUE

IF OK

REMOVE SIDE COVER CHECK 1-2 SHIFT VALVE TRAIN-MAY BE STUCK

FREE VALVE TRAIN IF POSSIBLE OR REPLACE CONTROL VALVE ASSEMBLY LEAKS A. INSPECT OIL PAN AND GASKETS MAKING CERTAIN SCREWS ARE PROPERLY TORQUED. B. INSPECT SIDE COVER FOR CRACKS, LEAKING GASKETS, AND PROPER SCREW TORQUE. C. CHECK BOLT TORQUE ON THE GOVERNOR COVER. CHECK "O" RING GROOVE FOR POROSITY. D. INSPECT SPEEDO "O" RING. E. CHECK RIGHT AND LEFT AXLE SEALS FOR CUTS, CRACKS OR MISSING GARTER SPRING. F. INSPECT SERVO COVER FOR DAMAGE AND POROSITY. G. INSPECT ELECTRICAL CONNECTOR AND ELECTRICAL CONNECTOR "O" RING SEAL FOR DAMAGE. H. INSPECT MODULATOR "O" RING FOR NICKS OR CUTS. I. INSPECT THE FILL TUBE FOR CRACKS. J. INSPECT THROTTLE VALVE (T.V.) CABLE, "O" RINGS, AND CASE BORE FOR SCORING OR POROSITY. K. INSPECT LINE AND GOVERNOR OIL PRESSURE PLUGS TO MAKE CERTAIN THEY ARE PROPERLY TORQUED AND THAT THEY ARE NOT CROSS THREADED. L. INSPECT THE COOLER LINE FITTINGS OR COOLER AND MAKE CERTAIN THEY ARE NOT BLOCKED OR RESTRICTED; CHECK THE COOLER LINES FOR CORROSION. MAKE CERTAIN THE LINES ARE INSTALLED PROPERLY AND NOT DAMAGED.

TORQUE CONVERTER CLUTCH (T.C.C.) SHUDDER A. VERIFY THAT THE ENGINE IS PROPERLY TUNED.

HARSH 3-2 DOWNSHIFT AT 25-35 MPH SHIFT "BUSYNESS" AT HIGHWAY SPEEDS DELAYED/HARSH 1-2 AND 2-3 UPSHIFTS AT LOWER SPEEDS ENGINE BREAKING DURING 2-1 MANUAL DOWNSHIFT AT 25-30 MPH HARSH 4-2 DOWNSHIFT AT 45-55 MPH *** --------------------------------------------------------------------- CADILLAC ONLY (SEE T85-53) ---------------------------- A. TO REPAIR ANY OF THESE FIVE CONDITIONS ON CADILLAC "AY" MODELS WITH JULIAN DATE OF 224 OR LOWER USE THE FOLLOWING PROCEDURE: REMOVE THE CONTROL VALVE ASSEMBLY AS OUTLINED IN SECTION 7-A ON CAR SERVICE FOR PROPER PROCEDURES. INSTALL PARTS CONTAINED IN SERVICE PACKAGE 8646936. B. INSTALL THE CONTROL VALVE ASSEMBLY ONTO THE TRANSAXLE WITH NEW INNER AND OUTER SPACER PLATE GASKETS AS OUTLINED IN YOUR ON CAR SERVICE SECTION 7-A FOR THE CORRECT LOCATION OF CHECK BALLS. RETAIN THE CHECK BALLS IN PLACE WITH PETROLATUM. INSTALL THE SIDE COVER WITH NEW GASKETS. ------------------------------------------------------------------- OLDSMOBILE ONLY --------------- AN ENGINE MISS CONDITION RESULTING FROM A CAUSE SUCH AS A CRACKED SPARK PLUG OR FAULTY INJECTOR MAY BE MISDIAGNOSED AS A TCC SHUDDER CONDITION. VERIFY THAT ENGINE IS OPERATING PROPERLY. IF SHUDDER CONDITION STILL EXISTS, CONTACT TECHNICAL ASSISTANCE COMMUNICATION SYSTEM FOR AN EXCHANGE UNIT.

A REVISED CALIBRATION 3-2 DOWNSHIFT SPRING FOR THE VALVE BODY MAY BE OBTAINED FROM THE TECNICAL ASSISTANCE COMMUNICATION SYSTEM TO CORRECT THIS CONDITION. PROVIDE MODEL NUMBER AND JULIAN DATE OF TRANSMISSION. OLDS TECHNICAL BULLETIN 85-T-6 EXPLAINS TRANSAXLE IDENTIFICATION OF THIS INFORMATION.

------------------------------------------------------------------- CHEVROLET ONLY ---------------- DO NOT CONTACT CHEVROLET TECHNICAL ASSISTANCE FOR AN EXCHANGE UNIT. FOLLOW THE PROCEDURES PREVIOUSLY RELEASED. ------------------------------------------------------------------

THE FOLLOWING IS A LIST OF THE PARTS THAT CAN BE SERVICED ON CAR (ATTACHING SCREWS, BOLTS, AND CONICAL WASHERS ARE NOT INCLUDED). THE PART REFERENCE NUMBER, FOLLOWING THE PART NAME, IS THE SAME NUMBER FOUND IN THE SERVICE MANUAL 440-T4 SECTION AND THE PARTS ILLUSTRATION. MODULATOR .......................................#19 MODULATOR "O" RING ..............................#18 MODULATOR RETAINER ..............................#20 MODULATOR BOLT ..................................#21 MODULATOR VALVE .................................#17 GOVERNOR COVER ..................................# 9 GOVERNOR COVER "O" RING .........................# 8 GOVERNOR THRUST BEARING .........................# 7 SPEEDO DRIVE GEAR ...............................# 6 GOVERNOR ASSEMBLY ...............................# 5 SIDE COVER ......................................#51 SIDE COVER GASKET ...............................#64 SIDE COVER/CHANNEL PLATE ........................#65 OIL PUMP ASSEMBLY ...............................#44 (AND RELATED SUB-ASSEMBLIES) T.V. LEVER AND BRACKET ASM ......................#50 T.V. LINK .......................................#49 SERVO PIPE RETAINER .............................#133 CONTROL VALVE ASSEMBLY ..........................#35 ALIGNMENT SLEEVE ................................#406 DETENT SPRING AND ROLLER ASM ....................#707 T.C.C. WIRING HARNESS ...........................#61 CLIPS (HARNESS) .................................#62 AND 67 CASE CONNECTOR ..................................#23 CASE CONNECTOR "O" RING .........................#18 SOLENOID ASSEMBLY ...............................#328 SOLENOID "O" RING ...............................#329 SPACER PLATE ....................................#31 SPACER PLATE GASEKT C/P .........................#30 SPACER PLATE GASKET S.P./V.B. ...................#32 OIL PUMP DRIVE DHAFT ............................#29 O.P. DRIVE SHAFT "O" SHAFT RING .................#28 MAGNET ..........................................#66 TRANS. OIL PAN ..................................#59 TRANS. OIL PAN GASKET ...........................#63 FILTER ASSEMBLY .................................#58 GOVERNOR OIL PIPE RETAINER ......................#129 GOVERNOR RETAINER GASKET.........................#128 GOVERNOR FEED SCREEN ............................#126 GOVERNOR FEED PIPE ..............................#125 GOVERNOR RETURN PIPE ............................#124 LUBE PIPE - FINAL DRIVE .........................#123 ACCUMULATOR COVER ...............................#121 F.D. LUBE PIPE BRACKET ..........................#143 ACCUMULATOR COVER GASKETS .......................#119 ACCUMULATOR COVER SPACER PLATE ..................#120 ACCUMULATOR PINS ................................#111 AND 115 1-2 ACCUMULATOR SPRING ..........................#116 ACCUMULATOR PISTON SEALS ........................#117 1-2 PISTON ......................................#118 3-4 ACCUMULATOR SPRING ..........................#112 3-4 ACCUMULATOR PISTON ..........................#114 DRIVE SPROCKET SUPPORT LUBE PIPE ................#110 LUBE PIPE RETAINER ..............................#109 LUBE PIPE RETAINER "O" RING .....................#108 OIL SCOOP .......................................#106 1-2 SERVO BRACKET ...............................#148 COOLER CONNECTORS ...............................#526 AND 569 THERMO ELEMENT ..................................#102 THRU 105 AXLE OIL SEALS ..................................#405 AND 540 VENT ASSEMBLY ...................................#528 PIPE PLUG .......................................#529

REFER TO SECTION 7-A IN THE SERVICE MANUAL FOR THE APPROPRIATE SERVICE PROCEDURES. NOTICE: IF REPAIRS REQUIRE REMOVAL OR DISASSEMBLY OF THE CHANNEL PLATE, THE TRANSAXLE MUST BE REMOVED AND REPLACED WITH AN EXCHANGE UNIT.

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.