Conditions for Setting the DTC: P0777
WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The TCM detects that the off going gear ratio remains the same even though it is commanded off for 1 second after a shift is commanded.