Sierra 1500 4WD V8-6.0L (2007)
Control Module: All Technical Service Bulletins
A/T - Harsh 1-2 Shift at Light Throttle
TECHNICAL
Bulletin No.: 10-07-30-003
Date: January 25, 2010
Subject: Harsh 1-2 Shift at Light Throttle (Follow Bulletin Diagnostic Steps then Reprogram TCM, if Necessary)
Models:
2007-2008 Chevrolet Avalanche, Silverado, Suburban
2007-2008 GMC Sierra, Yukon XL
All Equipped with 6.0L Engine (RPO L76) and 4L70E Automatic Transmission (RPO M70)
Please Refer to GMVIS
Condition
Some customers may comment about a harsh 1-2 shift at light throttle.
Cause
This condition may be caused by excessive adapt pressure added to the lowest shift adapt cells (0-3), which cannot be viewed using the Tech 2(R).
Correction
A new calibration has been developed to correct this condition. Follow the procedure below.
1. Verify the customer's concern by driving the vehicle between 1-7% throttle.
2. If shifts are harsh in this throttle range, clear adapts. Adapts for shifts at these light throttles do not appear on the Tech 2(R).
3. If shifts are still harsh after clearing adapts, this calibration will not help resolve the issue. Follow normal diagnostic procedures outlined in SI
under Slipping or Harsh 1-2 Shift.
4. If shifts are improved after clearing adapts, flash the vehicle's Transmission Control Module. A revised transmission calibration has been
developed to address these issues. Reprogram the transmission control module (TCM) with updated calibration files using the TIS2WEB Service
Programming System (SPS) application. Select SEQ Programming Sequence ECM/TCM from the Supported Controllers screen. Refer to SI and
Service Programming System (SPS) documentation for programming instructions, if required.
5. Confirm the new calibration in vehicle by performing at least ten (10) 1-2 shifts at 1-7% throttle with no recurrence of the issue.
Warranty Information
For vehicles repaired under warranty, use the table above.
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