This Preliminary information communicates to the dealer technician that engineering is investigating root cause of a harsh 1-2 and/or 5-4 shift on the 2017 Chevrolet Colorado and the 2017 GMC Canyon after mileage accumulation of approximately 25,000 miles. This Pi has been updated to refer the dealer technician to bulletin 21-NA-076 for information on how to address this concern.
