Here's an update on the interaction with the dealership today..
I went down there today on my lunch break and asked them for documentation from the service manual showing what the normal operating temperatures were for the vehicle. They told me that normal "hot" temps are 160 degrees to 200 degrees.
I asked the service manager if he could explain why so much heat was being generated by the transmission while in park, and if that too was considered "normal" behavior. They never said yes, but kept referring to the following page from the GM online service guide. (attached image).
Although this page describes the "hot procedure" for checking transmission fluid. It just implies that hot operating temperatures are 160-200 degrees.
The service manager kept saying that if the transmission was really overheating that the computer would say so.
Still...
The video doesn't lie as far as I'm concerned. How does the tranny heat up like that in park?
Thinking about going to my normal mechanic (who I trust) and asking for help from him on figuring this out. Don't want him to do anything that'll void the warranty..just want help researching it.
If this really is how a new Chevy transmission is designed to operate, I'll suck it up and shut up. But this sure does seem weird to me.
-Warren