Did they make a 2.8L Turbo? When I shut her down she makes a growling sound like a jet engine shutting down, Sounds great but don't know what it is....

 

Sounds like your coolant fan on the passenger side (smaller fan)- I have heard that a rubber liner becomes loose and could cause this sound- open your hood (engine off)and look with a flash light- then start the engine turn on your AC so the fan comes on and see if that is it- Mine makes the same noise during extremely hot days- I live in the NE