Silverado 3500 2WD V8-6.6L DSL Turbo (2006)
Control Module: All Technical Service Bulletins
A/T Controls - Shudder in 6th Gear
Bulletin No.: 06-07-30-013
Date: May 30, 2006
TECHNICAL
Subject:
Allison Transmission - Vehicle Shudder When Driving in 6th Gear Range (Reprogram Transmission Control Module (TCM))
Models:
2006 Chevrolet Silverado 2500 (3/4 Ton) and 3500 (1 Ton) Series
2006 GMC Sierra 2500 (3/4 Ton) and 3500 (1 Ton) Series
with 6.6L Diesel Engine (RPO LBZ/LLY) and Allison Transmission (RPO MW7)
Condition
Some customers may comment on a shudder that is only present at vehicle speeds between 74 km/h (46 mph) and 79 km/h (49 mph) when driving at
constant speed in 6th gear range in Four-Wheel High mode.
Correction
A new calibration has been released to correct this condition. This new calibration will change the minimum powered 6-5 downshift point to
approximately 82 km/h (51 mph), allowing the transmission downshift to occur prior to the speed and load range that causes the shudder.
Reprogram the transmission control module (TCM) with the new service calibrations contained in TIS version 6.0 or later, which was released on May
28, 2006.
Warranty Information
For vehicles repaired under warranty, use the table.
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