TxAgMojo

I had this same issue recently on my 2021 Yukon AT4. - no engine light but same symptoms mentioned in above thread - replaced valve body (no change) - replaced torque converter - - O2 sensor warning comes on - Replace O2 Sensor and shutter/shift problem goes away and increase MPG +3 My Recommendation if no engine light or error message is showing then change out O2 sensor. Mine didn’t show as bad till the torque converter was replaced. Bad O2 sensor symptoms reflect the issues in this thread.