Engine Controls - 4L60E/4L65E A/T, 2-3 Shift Clunk Noise
Bulletin No.: 05-07-30-012Date: May 09, 2005
TECHNICAL
Subject:
4L60-E/4L65-E Automatic Transmission 2-3 Shift Clunk (Reprogram Powertrain Control Module (PCM)
Models:
2005 Cadillac Escalade
2005 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2005 GMC Sierra, Yukon
with 4L60-E (RPO M30) or 4L65-E (RPO M32) Automatic Transmission
Condition
Some customers may comment on a 2-3 shift clunk noise. Typically, this clunk noise is most noticeable when the 2-3 shift occurs under approximately 48 km/h (30 mph).
Correction
Important:
^ The PCM calibrations may REDUCE but not ELIMINATE the 2-3 shift clunk.
^ This bulletin only applies to the 2005 model year vehicles listed above.
^ As always, make sure your TECH 2(R) is updated with the latest software version.
1. To determine if this calibration will help to reduce 2-3 shift clunk, use the Tech 2 to navigate to the transmission diagnostic section and view the 2-3 shift adapt cells.
^ If the 2-3 adapt cell values are negative, this calibration change will have minimal benefit in reducing the 2-3 shift clunk.
^ If the 2-3 adapt cell values are above approximately + 5 psi, this calibration may provide a reduction in the 2-3 shift clunk.
Important:
These calibrations also contain the second gear start correction as detailed in bulletin 05-07-30-013.
2. Technicians are to reprogram the PCM with an updated software calibration. This new service calibration was released with TIS satellite data update version 5 or later available May 1, 2005. Refer to Service Programming System (SPS) in Vehicle Control Systems in the appropriate SI Document.
Warranty Information
For vehicles repaired under warranty, use the table.
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