2016 Ram 1500 quad cab v6 noise under hood when off

[John Cardinale]

truck dead, battery died, used battery charger, got it started, then when I turned it off, I started hearing a squeek / squeel noise like air leaking, maybe a compression leak.

here is link to video.

https://photos.app.goo.gl/OcKqXM0ArpAzBAzu2

Any ideas? truck has under 6k miles..