A/T - Shudder Or RPM Fluctuation In 4th,5th, or 6th Gear
32 Shudder or RPM fluctuations while at cruising speed
32 12 03
2028608/1
February 3, 2012.
217
Affected Vehicles
Condition
Customer may report shudder or RPM fluctuation while at cruising speed in 4th, 5th, or 6th gear.
Technical Background
Torque convertor clutches may have excess slippage while cruising.
Production Solution
Not applicable.
Service
1. Check and verify that the software is at the highest level using TSB 2028053, 37 TCM software update for downshift concerns or 2028279, 37
Shift concerns when slowing vehicle. Also, check that the fluid level and condition is clean, full, and matches the required color per the applicable
TSB.
Tip: If needed, update the software of the transmission and change the fluid before proceeding with this TSB.
2. Test drive the vehicle to verify the concern is present.
If the concern can be duplicated, verify there are no fault codes stored for misfires and watch the Measure Value Blocks in the ECM to verify no
misfires are seen when the condition is present.
3. Check MVB 7 from the TCM. Verify Field 3 is reading control and record the slip count from Field 4 while the concern is present. The slippage
of the TCC should not exceed 120 RPM in MVB 7 field 4 while the convertor is in control mode. The RPM surge should coincide with TCC
slippage. If this reads higher than 120 RPM, the torque convertor should be replaced.
Tip: The TCC slippage will vary when in open TCC mode and should read 0 when in closed TCC mode, this is normal. Replace the convertor for
high slippage when the TCC is in control mode (above 120 RPM) or for any slippage when in closed mode (MVB 7 field 4).
Tip: It is not necessary to receive a Repair Authorization to perform this TSB.
218
Warranty
Additional Information
One of the following Technical DIAGNOSIS AND REPAIR(s) will be necessary to complete this procedure:
^ TSB 2028053, 37 TCM software update for downshift concerns
^ TSB 2028279, 37 Shift concerns when slowing vehicle
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service
manuals for the latest information.
