Ok, so I have the same Knocking during turn off, and since one of my good friends works for chrysler I brought it to his shop.

He thinks it might be the crank bearings... (Bad News)

Check to see if you notice this... Try to listen for a knocking sound when you pull up in your driveway. It is very quite cuz our car is so loud, when you turn off the car it knocks...

When you dont hear the knocking during idle, there is no knocking during de-ignition. (Yes I just invented that word)

we are gonna throw it up on the lift and figure it all out this week