A/T - Intermittent Powertrain Shudder

NO: 21-13-95 Rev.

GROUP: Transmission

DATE: Sep. 8, 1995

SUBJECT:
Intermittent Powertrain Shudder

NOTE:
This bulletin supersedes Technical Service Bulletin 21-13-95, dated Sep. 1, 1995, which should be removed from your files. The revision corrects a Labor Operation Number and is highlighted with **asterisks**.

MODELS:
1996 (NS) Town & Country/Caravan/Voyager
1996 (GS) Chrysler Voyager (European Market)

NOTE:
This bulletin applies to vehicles equipped with a 41TE transaxle.

SYMPTOM/CONDITION:

Intermittent powertrain shudder during A/C operation while the transaxle is in 3rd or 4th gear and the Electronically Modulated Convertor Clutch (EMCC) is fully engaged (torque convertor is locked) or Diagnostic Trouble Code (DTC) 73 (Worn Out/Burnt Transaxle Fluid) is present in the Transaxle Control Module (TCM).

These vehicles use an EMCC strategy to allow the torque convertor to "cushion" the A/C compressor clutch engagement while in 3rd and 4th gear when the torque convertor is locked. Transmissions with fluid deterioration from excessive heat exposure or extensive A/C operation in 3rd and 4th gear when the torque convertor clutch is applied may exhibit a pronounced shudder during A/C compressor clutch engagements.

The TCM will detect this shudder. After 20 consecutive shudder events are detected the TCM will set DTC 73 and disable the EMCC strategy. If EMCC has been disabled a slight bump may be felt when the A/C compressor clutch engages while running on smooth roads with the torque convertor locked. After 35 On Board Diagnostics II (OBD II) warm-up cycles (a warm-up cycle is when the engine coolant temperature has risen by at least 40° F since engine start up and reaches a minimum engine temperature exceeds 160° F), the TCM will re-attempt the EMCC strategy at least once, so a vehicle with DTC 73 present may experience intermittent powertrain shudder.

DIAGNOSIS:

Using the Mopar Diagnostic System (MDS) or the Scan Tool (DRB III) check for the presence of DTC 73 in the TCM. If DTC 73 is found, perform the Repair Procedure.

If DTC 73 is not present, road test the vehicle while monitoring the in-gear condition of the transaxle with the DRB III and the NC selected (ambient temperature must be above 45° F for the A/C clutch to cycle).

Verify whether shudder occurs when the transaxle momentarily enters 4th gear partial lock from 4th gear lock or 3rd gear partial lock from 3rd gear lock. Throttle angles of more than 20 degrees at 60-65 MPH will produce the most noticeable shudder. The vehicle should be evaluated with the transaxle both cold (transaxle temperature below 100° F) and warm (transaxle temperature above 200° F) while in 4th gear lock. If the shudder condition occurs and/or the transaxle fluid is discolored, even if a DTC is not present, perform steps 1 and 2 of the Repair Procedure.

PARTS REQUIRED:

AR 4798233 Fluid, Mopar ATF - Type 7176
1 4504048 Package, Oil Filter
AR 4318025 Sealant, RTV

REPAIR PROCEDURE:

This bulletin involves evaluating the vehicle cooling system, changing the transaxle fluid two times and on some vehicles clearing the DTC's from the TCM.

1. Evaluate the vehicle cooling system and ensure proper function.
2. Change the transmission fluid two times using the following procedure:

A) Raise the vehicle with an appropriate hoist.
B) Clean the transaxle oil pan and mating area thoroughly.
C) Remove the transaxle oil pan. Remove all sealant from the transaxle oil pan and mating surface of the transaxle. Clean the inside of the oil pan and magnet.
D) Separate the transaxle oil filter and 0-ring from the valve body and discard.
E) Install the new oil filter package P/N 4504048.
F) Apply an 1/8 in. bead of Mopar RTV sealant, P/N 4318025, on the mounting flange of the transaxle oil pan. Torque the attaching bolts to 19 Nm (165 in. lbs.).


NOTE:
Use only Mopar ATF Plus Automatic Transmission Fluid Type 7176 (p/n 4798233). Use of Dexron IIE or Dexron III may cause clutch shudder.
G) Pour 4 quarts Mopar Automatic Transmission Fluid Type 7176 through the fill tube.
H) Start the engine and allow to idle for a minimum of one minute. With the parking brake and the service brakes applied, move the gear selector lever momentarily to each gear position. Place the gear selector lever in either Park or Neutral.
J) Check the transaxle fluid level and add an appropriate amount of transmission fluid to bring the level to 1/8 in. (3 mm) below the ADD mark on dipstick.
K) Recheck the fluid level after the transaxle is at normal operating temperature. The level should be in the HOT range of the dipstick.
L) Drive the vehicle at least 10 miles.
M) Repeat steps 2A - 2C then go to step 2N.
N) Separate the transaxle oil filter and 0-ring from the valve body and drain the fluid from it. This also allows for additional fluid to drain from the transmission.
P) After the transmission fluid has stopped draining, be sure the 0-ring is not damaged, then reinstall the transaxle oil filter and 0-ring to the valve body.
R) Repeat steps 2G - 2K then go to step 3 if appropriate.

3. For vehicles with DTC 73 present, the following battery disconnect procedure must be followed to enable the EMCC feature for A/C clutch engagement cushioning:


NOTE:
If the DRB III is at release level 17.2 (dated 8/22/95) the battery disconnect feature in the Transmission Miscellaneous Menu can be used and allows the technician to be able to skip to step 3D and disregard step 3E.

A) Record the radio station presets.
B) Disconnect the negative battery cable and then reconnect.
C) Use the DRB III to verify the TCM has recorded DTC 12 (battery disconnect). If it has not, disconnect the negative battery cable for a longer period of time that will set DTC 12.
D) Use the DRB III to clear the TCM DTC's.
E) Program the radio station presets and set the clock.

4. Road test the vehicle to verify EMCC is operational during A/C clutch engagement and no perceptible shudder occurs after driving 5 miles. Initially, shudder may occur for a few miles until the new fluid penetrates the torque convertor clutch disc.


POLICY: Reimbursable within the provisions of the warranty.


TIME ALLOWANCE:
Labor Operation No: 21-00-10-93 Check for DTC's, Change Transaxle Fluid, Road
Test, Change Transaxle Fluid 2.5 Hrs.

**21-00-10-94** Check for DTC's, Change Transaxle Fluid,
Road Test, Change Transaxle Fluid, Disconnect Battery and
Check for DTC 12, Road Test 2.6 Hrs.

FAILURE CODE: XX - Service Adjustment