C 230 (203.052) V6-2.5L (272.920) (2007)
Clutch: All Technical Service Bulletins
A/T - Harsh 1-2/3-2 And 2-1 Shifts
Date: November 20, 2008
Order No.: S-B-27.60/61j
Supersedes: P-B-27.60/61i dated August 21, 2007 and T-B-27.60/62i dated Dec. 4, 2007
Group: 27
Revision History
SUBJECT:
All Models with Automatic Transmission 722.9, 7G-Tronic (NAG2) Uncomfortable Shift Quality of 1-2, 3-2 and 2-1 Gear shifts
If you receive customer reports in the above model vehicles of rough 1-2, 3-2 and 2-1 gearshifts, this may be due to the specific gear not being fully
adapted or there could also be a mechanical cause as well. To resolve, perform the following diagnostic sequence.
1. Reproduce the complaint and identify the affected shifts using Star Diagnosis.
2. Print out adaptation data in the form of a transmission control unit log (do not reset the adaptation values).
3. Re-adapt the problem shift using the adaptation process in Star Diagnosis and print a post process transmission control unit log.
NOTE:
For downshifts, the vehicle must coast to a stop without braking in order for adaptation to occur.
For upshifts, the vehicle must be driven and shifted within the valid torque window (green zone in torque display in Star Diagnosis).
If the condition still exists after adaptation, compare adaptation values before and after adaptation test drive. If the values for the filling times of these
shift operations are close to the negative limit of -20 cycles (between -15 and -20), but move further into the negative with further adaptation, this may
have the following cause / remedy.
Cause A - An incorrectly installed retaining ring for return spring B1 or B3.
Remedy A:
1. Remove the transmission
2. Disassemble multi-disk brake B1& B3
3. Remove / install / replace retaining ring and disk spring. Refer to test/repair work procedure in WIS document AR27.50-P-0870W and
AR27.50-P-0890W.