TCC - Acceleration Shudder/DTC 38 Set
NO: 18-05-94GROUP: Vehicle Performance
DATE: Apr. 8, 1994
SUBJECT:
Vehicle Shudder During Torque Convertor EMCC Operation
MODELS:
1993 - 1994 (AA) Acclaim/Spirit/LeBaron Sedan
1993 (AC) Dynasty/New Yorker/New Yorker Salon
1993 (AG) Daytona
1993 - 1994 (AJ) LeBaron Coupe/LeBaron Convertible
1993 - 1994 (AP) Sundance/Shadow
1993 - 1994 (AS) Caravan/Voyager/Town & Country
1992 - 1993 (AY) Imperial/New Yorker Fifth Avenue (Built After MDH 02-08-92)
1993 - 1994 (LH) Concorde/Intrepid/Vision
1994 (LH) LHS/New Yorker
NOTE:
THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH THE 41TE OR 42LE AUTOMATIC TRANSMISSION.
SYMPTOM/CONDITION:
Light to moderate acceleration shudder during torque converter EMCC (Electronic Modulated Converter Clutch) operation. Most noticeable on smooth roads, or on long, moderate uphill grades (depending on final drive ratio, approximately 28 to 42 MPH).
This shudder condition is generally the result of leakage in the transmission front pump caused by a worn pump bushing. It is sometimes accompanied by pump whine and Diagnostic Trouble Code 38 (Torque Converter Control Out of Range).
DIAGNOSIS:
Using the Mopar Diagnostic System (MDS) or the Scan Tool (DRB II or III) with appropriate diagnostic procedure manual, verify that all engine/transmission systems are functioning as designed. If Diagnostic Trouble Codes (DTC's) are present, record them on the repair order for future reference, and repair as necessary. If Diagnostic Trouble Code 38 is present, proceed to the repair procedure. If no codes are present and all systems are functioning correctly, proceed with the following:
A. Inspect the engine mounts for signs of deterioration or grounding. Repair or replace as necessary.
B. Inspect all rotating components such as halfshafts, brake rotors, tires and wheels for any abnormal conditions that could contribute to low frequency vibrations.
C. Road test the vehicle at normal operating temperatures while monitoring transmission performance using a DRB II or III. Use the RPM display screen, in the transmission diagnostic section, to display converter clutch function and throttle angle. EMCC shudder generally is encountered at 10 to 15 degrees throttle on smooth roads between 38 to 42 MPH depending on final drive ratio. The PRNDL readout on the DRB II or III can be either "3PL" or "4PL" during the shudder. To verify that the shudder is EMCC induced, the EMCC feature should be disengaged. This can be done by accelerating at medium/heavy throttle, or lightly depressing the brake pedal, or disengaging the throttle. If after doing any of these and the shudder disappears, go to the repair procedure.
PARTS REQUIRED:
REPAIR PROCEDURE:
This bulletin involves replacing the transmission front pump assembly and the transmission torque converter with one that has bonded converter clutch friction material.
1. Following the procedures outlined in the appropriate Service Manual, replace the torque converter and the transmission front pump assembly with the parts identified in the parts section of this bulletin.
2. Perform the transmission oil cooler and lines reverse flushing and flow check procedure as outlined in the appropriate Service Manual.
3. Before performing the torque converter clutch break in reset procedure verify that the repair has corrected the shudder condition. Drive the vehicle under the same conditions that caused the shudder. If the condition is corrected, go to step four.
NOTE:
SOME LIGHT SHUDDER MAY BE PRESENT BEFORE RESETTING THE EMCC BREAK-IN PROCEDURE. If severe shudder is still present, refer to the diagnostic section of this bulletin and re-evaluate the items listed.
4. Using the DRB II or III Scan Tool, perform the Torque Converter Clutch Break-in Procedure listed in the appropriate Service Manual.
POLICY:
Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
Labor Operation No:
21-60-05-91 1993 - 1994 AA, AC, AG, AP, AS &
1992 - 1993 AY 6.1 Hrs.
1993 - 1994 LH 7.1 Hrs.
21-00-05-63 1993 - 1994 AS (Anti-Lock Brake System Equipped) 0.2 Hrs.
21-00-05-64 1993 - 1994 AS (All Wheel Drive Equipped) 1.2 Hrs.
FAILURE CODE: 52 - Improperly Machined