This vehicle suffers from a torque converter/transmission shudder after the transfer mission fluid heats up. My initial complaint to the selling dealer and they did not follow the GM posted procedure and initially charged me for the service. Iave changed dealerships and Iave been told it the temporary fix is to do a flush and there is no permanent fix by GM. I have had situations where and unexperienced driver would have definitely got into a car accident and I donat let anybody drive my car because I believe it is unsafe. So far the dealer has been accommodating while under warranty but advised I reach out to GM who then advised to review my documents I file an NHTSA complaint. What occurs when the vehicle is not in warranty and the vehicle continues to shudder. I have included the service bulletin and repair invoices.