4L60E Autopsy - No Movement Mystery

I received this 2010 4L60E out of a Chevrolet Colorado where the primary shop's customer advised of an intermittent no-movement condition. The owner had the truck towed to the shop where the tech was able to pull it into the bay under its own power and could not duplicate the no-movement condition. I tear down and inspect the transmission, trying to determine what may have caused the lack of movement the customer had reported and discover a few other things along the way.