Trouble Shooting
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, 2003 Chevrolet Cab & Chassis Silverado, and 2002 GMC Sierra. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Transmission malfunctions may be caused by poor engine performance, improper adjustments, fluid condition or failure of hydraulic, mechanical or electronic components. Ensure all concerns have been properly checked prior to transmission overhaul. For additional diagnosis and testing procedures, see appropriate ALLISON LCT
1000 SERIES DIAGNOSIS article.