I have a 2018 Canyon which I bought used with only 15K miles on it. I've had this Torque Converter shudder that I feel through several of the shifts. Sometimes it's really pronounced, sometimes not, but I can always get it to happen on a slight hill.
I've brought it to 3 different GM Dealerships at the request of the dealership I purchased it from. All 3 have said that the feel the shudder but that they can't change the torque converter. They all also said that they used to be able to change it but GM is telling them now that they can't, have to do the triple fluid flush, which I've also had done 3 times. The last dealer told me that it was going to cost him $1800 for the part and he didn't want to be out that money if GM didn't back him on the warranty.
I opened a case with GM and each time I call them to find out what can be done they say really nothing can be done other than the triple flush.
I spent a lot of money on this truck and I absolutely WILL NOT buy another GM product like this!!!!!