3-2 FLARE DURING DOWNSHIFT SERVICE PACKAGE /325-4L TRANS

BEGINNING, FEBRUARY 1982, ALL MODELS OF THE 1982 THM 325-4L TRANSMISSIONS WERE BUILT WITH REVISED CALIBRATION. THIS CALIBRATION CHANGE WILL PREVENT ENGINE FLARE DURING A 3-2 DETENT DOWNSHIFT AT APPROXIMATELY 40-50 KMPH (25-30 MPH) ONLY. CHECK FOR THIS FLARE CONDITION IN BOTH DRIVE AND MANUAL THIRD RANGES. TO CORRECT A 3-2 DETENT DOWNSHIFT FLARE ON ANY THM 325-4L TRANSMISSION BUILT BEFORE THIS CALIBRATION CHANGE, USE THE FOLLOWING SERVICE PACKAGE: MODEL AM SERIAL NUMBER 4989 *SERVICE PACKAGE NO. 8635930 MODEL BE SERIAL NUMBER 6681 *SERVICE PACKAGE NO. 8635930 MODEL BJ SERIAL NUMBER 1301 *SERVICE PACKAGE NO. 8635930 MODEL AL SERIAL NUMBER 7111 *SERVICE PACKAGE NO. 8635931 MODEL OK SERIAL NUMBER 10946 *SERVICE PACKAGE NO. 8635931 MODEL AJ SERIAL NUMBER 22392 *SERVICE PACKAGE NO. 8635932 MODEL AG SERIAL NUMBER 1246 *SERVICE PACKAGE NO. 8635932 MODEL AB SERIAL NUMBER ALL *SERVICE PACKAGE NO. 8635932 MODEL OE SERIAL NUMBER 35224 *SERVICE PACKAGE NO. 8635933 * EACH OF THESE SERVICE PACKAGES WILL CONTAIN A NEW DESIGN 1-2 SHIFT VALVE, LO-1ST DETENT VALVE, LO-1ST DETENT VALVE BUSHING AND AN INSTRUCTION SHEET. SERVICE INFORMATION: WHEN DIAGNOSING A 3-2 DETENT DOWNSHIFT FLARE BE CERTAIN TO MAKE THE FOLLOWING CHECK BEFORE USING THE ABOVE SERVICE PACKAGE: 1.CHECK INNER AND OUTER INTERMEDIATE PISTONS AND SEALS FOR WEAR, CRACKS, BURRS, FOREIGN MATERIAL, ETC., REPLACE IF NECESSARY. 2.CHECK THE VALVE BORE, BUSHINGS AND VALVES FOR BURRS, SCORING AND FOREIGN MATERIAL. 3.CHECK FOR A LOOSE D-2 PIPE. ON-CAR SERVICE SHOULD BE DONE. THE CONTROL VALVE ASSEMBLY MUST BE REMOVED IN ORDER TO REPLACE THE VALVES AND BUSHING. IT IS ADVISABLE TO INSPECT THE CONTROL VALVE TO SPACER PLATE GASKET, ROLL PINS AND OIL FILTER AND REPLACE IF NECESSARY. ENGINE FLARE DURING 3-2 DOWNSHIFT ON THM 325 AND THM 325-4L TRANSMISSION (1981-1982 "E" AND "K") CERTAIN 1981 AND 1982 E AND K MODELS CAN EXHIBIT AN ENGINE FLARE (OVERREVVING) CONDITION DURING A PART THROTTLE OR DETENT 3-2 TRANSMISSION DOWNSHIFT. A "PART-THROTTLE" MANUEVER REPRESENTS LESS THAN 3/4 THROTTLE (60F THROTTLE ANGLE VIA DIAGNOSTICS) WHILE A "DETENT" DOWNSHIFT IS AVAILABLE OVER 3/4 THROTTLE. THE PART THROTTLE ENGINE FLARE IS DUE TO INCORRECT TIMING FOR THE APPLICATION OF THE INTERMEDIATE BAND (2ND) CAUSING THE ENGINE SPEED INCREASE AFTER RELEASE OF DIRECT CLUTCH (3RD). THE ENGINE FLARE ON A DETENT MANUEVER IS DUE TO THE TRANSMISSION NOT COMPLETING THE SHIFT INTO 1ST GEAR AND THEN GOING TO 2ND GEAR (3-1-2). BOTH CONDITIONS ARE MOST NOTICEABLE IN THE VEHICLE SPEED RANGE OF 25-30 MPH AFTER THE TRANSMISSION HAS REACHED NORMAL OPERATING TEMPERATURE (IN 10-15 MINUTES). THIS CONDITION CAN BE DIAGNOSED IN BOTH DRIVE AND MANUAL THIRD SELECTOR POSITIONS. THIS BULLETIN OUTLINES SPECIFIC SERVICE PROCEDURES REQUIRED TO CORRECT THIS CONDITION ON EACH POWERTRAIN APPLICATION. DEPENDING ON MODEL YEAR AND ENGINE/TRANSMISSION COMBINATION, PROCEED AS FOLLOWS: YEAR 1981 ENGINE 4.1L V-6 TRANSMISSION THM 325 MODEL AG SECTION OF BULLETIN I YEAR 1982 ENGINE HT4100 TRANSMISSION THM 325-4L MODEL AJ SECTION OF BULLETIN II YEAR 1982 ENGINE 5.7L DIESEL TRANSMISSION THM 325-4L MODEL AL SECTION OF BULLETIN II YEAR 1982 ENGINE 5.7L DIESEL TRANSMISSION THM 325-4L MODEL AL SECTION OF BULLETIN III I.1981 "AG" MODEL * SEE BULLETIN FOR ADDITIONAL TEXT & ILLUSTRATIONS *

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.