I was lucky to have mine covered under the extended 7 year warranty I purchased. Had it done last May. Grateful I had that warranty or I probably would have had to pay. Best $2K i spent, Warranty is expiring end of October.
Had the trans issue now, almost out of warranty and the dealer covered it. 2015 Silverado LTZ 6.2L 8 speed. Looks like I got lucky . Temps seem a bit drastic, but I think that is why it was failing. Been shifting badly for years. Tried to find the parts they installed, but not what I've seen in this thread.