A/T - Jerking/Buzzing/Droning Noises

Date: February 28, 2007
Order No.: P-B-27.60/43c
Supersedes: P-B-27.60/43b dated March 23, 2006
Group: 27





Revision History

SUBJECT:
Model 170.466

Model 203.040/065/740

Model 211.065/070/076/082/083/265/282/283

Model 215.374

Model 220.174

Model 230.474/476

Equipped with 722.6 Automatic Transmission

Torque Converter Clutch Rough Engagement and/or Droning/Buzzing

If you receive customer reports in the above model vehicles that during acceleration and/or constant drive there is a noticeable jerk, possibly followed by a droning/buzzing, adapt the torque converter clutch as per the below procedure. This may be caused by a lack of/or inadequate adaption of the torque converter clutch. This particularly applies in cases where there is less than 6,000 miles accrued on the torque
converter or transmission control unit.

1. Read engine coolant temperature out with Star Diagnosis [Cars -> Vehicle Type -> control units -> ME -> Actual Values -> Test engine at idle speed].

Note:
Before starting the procedure, the engine coolant temperature must be below 20� C / 68� F.

2. Start the engine (cold start, over-night), select "D" with the shifter and hold the vehicle at idle speed for 20 seconds by depressing the brake pedal.

3. Start driving the vehicle between 30-40 mph on level ground using the cruise control. With SDS, observe the engine coolant temperature until the engine coolant temperature has risen approx. 10� C / 18� F.

Warning!
Hazardous procedure for one technician alone.

4. Stop driving and hold the vehicle in "D" at idle speed for 20 seconds by depressing the brake pedal.

5. Repeat steps 3 and 4 with each engine coolant temperature increase of about 10� C / 18� F until the operating temperature levels out.

6. After reaching a transmission oil temperature of 80� C / 176� F, continue driving between 30-40 mph, on level ground for 10 minutes cumulatively using the cruise control to maintain consistant engine load.

Note:
The following allowable labor operations should be used when submitting a warranty claim for this repair.





In Case of Warranty