A/T - Calibration Info for Allison MW7 6-Speed: Overview
Bulletin No.: 06-07-30-032Date: December 06, 2006
INFORMATION
Subject:
New Calibration Information for Allison(R) MW7 6-Speed Automatic Transmission Overheat Condition in Cold Ambient Temperatures (Less Than -40°C, -40°F) on Vehicles with Aftermarket Transmission Sump Heater and 6.6L Duramax(TM) Diesel Engine
Models:
2006-2007 Chevrolet Silverado Classic
2006-2007 GMC Sierra Classic
with 6.6L Duramax(TM) Diesel Engine (VINs D, 2 - RPOs LBZ, LLY) and Allison(R) LCT 1000 (RPO MW7) 6-Speed Automatic Transmission Allison MW7
Built Prior to the VIN Breakpoints shown.
Some customers, in colder climate areas, may elect to have an aftermarket transmission sump heater installed to assist in vehicle cold start warm up. Combining a transmission sump heater with systems incorporated in the vehicle to enhance the heater performance may cause the transmission to overheat/fail when the vehicle is started and left idling in the elevated idle mode.
To address this issue, a new transmission calibration has been released to alter the operating temperature range of the transmission component of elevated idle when a vehicle is equipped with a transmission sump heater. The calibration is made available on a Customer Pay basis as it is required based on the usage of an aftermarket automatic transmission sump heater. See Calibration Information Below.
A customer letter will be sent to all customers of record in cold climate areas to make them aware of this condition and a copy is included for your information. The following areas in the United States and Canada have temperature ranges that meet the criteria of temperatures less than -40°C (-40°F):
Alaska
Minnesota
Alberta
British Columbia
Manitoba
Newfoundland
Northwest Territories
Ontario
Quebec
Saskatchewan
Yukon
Please provide a copy of this information to customers of new vehicles built within the VIN range above that are purchased after the publication of this bulletin.
Module Reprogramming:
An updated TCM calibration is now available to address this concern. This calibration, or any that follow, is designed to address this concern. Refer to Service Programming System (SPS) using the appropriate Service Information (SI) procedures. The new TCM calibrations will be available to dealerships in the following TIS2WEB version (website version of TIS):
2006 and 2007 vehicles - TIS2WEB version 12 for 2006. Available now.
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