Finally, I can post! This forum would not let me join saying I was answering the security question wrong over and over but I guess the FB option worked. Anyways, wanted to post here to mark it for myself, I own a 2020 LTZ 1500 Duramax (couple weeks, 1000 miles). Mine leaks on the drivers side but can't notice any wetness on headliner, floor was soaked under rear seat, work a lot so can not be without my truck too long but my dealer will be getting an ear full regardless. Thank you to all of the members for all of the information. I read through about 10-20 pages random spots of the 99!