Had that exact same metallic clanking noise on my car many years ago. I had some vibration, though no bad shaking. The issue was the main AWD propeller shaft (drive shaft) to the rear. I'd start by removing that and see if it stops the sound (I'm sure it will). This will narrow it down to the AWD sy...

Most likely the center support bearing rubber has failed. As suggested remove the prop-shaft to the rear and see if the issue disappears. While under there check these too: 1) AWD system: Prop-shaft front bearing at angle gear, center support bearing, viscous coupling front bearing and VC casing fro...