We have a 1997 Chevy 454 big block with a 4L80E transmission with 39,000 miles on it. It was starting to whine. We had our transmission fluid changed. Pan was cleaned out with a couple of tablespoons of fine shavings. New fluid was put in. It ran fine for two weeks and then we were parking and we pulled up and went to back up and literally had no ability to shift in any gear. No limp mode. Luckily we were home. Feel blessed for that. We pulled the transmission pan again. It was still fairly clean but had 1/8 inch piece of metal but that’s it. No more shavings. We are stump that it just quit so suddenly with no more whining. We were leaning towards thinking a fuse or the tcm. Do you have a video on the tcm? Any thoughts? We have scanned the internet and you are the only one with a comprehensive explanation on anything close. Your video on the pcm described perfectly what is happening with my mother in law’s 2013 Silverado so I will have to let her know. Thanks in advance for any info on another video or general info you might give. 🙏