Technical Bulletin (ECM, TCM Software Update and Valve Body Replacement for Harsh Up - Down Shift from Transmission when Cold):
Customer may experience harsh up shift in gears 1-2 and 2-3, or harsh down shift in gears 3-2 and 2-1. The symptom is most noticeable at transmission temperatures below 60°C (140°F). No DTCs are stored in the TCM or the ECM for this complaint.
The production solution for this issue was updated transmission valve body, ECM and TCM software.
This document discusses the "Fault Codes" necessary to diagnosis, and potential remedy of the issue. The fault codes for checking warranty coverage for servicing the vehicle are also available.