Curious. Did you claim to have the shudder to them? Or did just ask for the service, because the TSB says they can do it without performing diagnostics?Not sure where people are coming up with this? I have a 2018 with no shudder issues. Printed the SB, and took it to 5 different dealers, and all claim it is true they don't have to do the required testing to satisfy GM any more, but all claim the shudder must be present for the free service.there is a TSB an Bulletin for them to change the fluid, no questions asked...
So if someone knows a Dealer in the outer Pittsburgh area west into Ohio I'd sure like to know, as I've had no luck and get the same story from them all.