Ouch. Very sorry about that. Hopefully I don't start having problems soon (36500 on my 2017)
I've been burning up Chevy trannies since 1980; THM350, 4T60E, 4T65E-HD been through em all.
Usually fail around 60k typically just after a fluid and filter change. Have around 90K on the latest one with Royal Purple trannie fluid installed since new and I vow to never change the fluid!
Just wondering are you the 1st owner?
Well, I've worked at GM dealers since late 2001(with exception 2 years at a Nissan dealer and 6mo at a BMW dealer) and every GM dealers transmission department was was behind. Meaning, they had more work than they could do. In my limited experience, only Nissan transmissions, CVT's specifically, and Ford built Mazda ECAT transmissions('88-'92) were worse. But, I had no SS customers with a failed transmission. I had a lot of FWD 4 and 6 speed trans failures though, from Cadillacs on down.
Oh, and most GM dealers can't repair a manual trans. The only one that I every saw was a young ambitious tranny guy who fixed the trans in my Firehawk, with my assistance and tools, back in 2004. All other times the trans was replaced because noone could fix it.