I had the triple flush done twice in two months in my 2015. The second being in August. Still have the shudder although not as bad but still very pronounced and bothersome. My dealer will no longer work on the car because they said their :cracker jack" mechanic said theres nothing wrong with my car and GM's customer service is non existent. I have an adviser, an incident number but they aren't doing diddly squat. Yesterday, out of sheer frustration, I tried this stuff called Lubegard. Injected 4 oz into my transmission and as soon as I drove the car, the shudder was gone. It was shuddering at 8am when I drove it to warm up the fluids and not shuddering at 9:30 when I was done with the work. Drove the car close to 75 miles all day and no shudder..........I will update but check out their website.