Can anyone help me identify this CATASTROPIC engine noise?

Well, I'm not ready to give up on my old trusted 6.5 yet (see signature for info).

I had a pretty horrible experience yesterday. I was out driving, and suddenly my engine produced a VERY loud and VERY bad, catastropic-like noise.

This is the sound from the cabin while driving (loud noise level warning).


I immediately thought it was the gears making the sound, so I put it in neutral, but the sound persisted and was unchanged. I noticed that if I gave full throttle, the sound would dissapear until I let my foot off the pedal again.

I then thought I had lost an engine oil line, but after a quick look at the oil pressure gage, it was good.

I did not notice perfomance loss.

Then I thought the engine might have shaked off a motor mount, but in inspection, there is no irregular movement on the engine.

Then I thought a turbo fan blade might have snapped and been left in the turbo housing, but in inspection, the turbo fan blades are operating normally and smoothly.

Luckily, I was close to home and managed to drive it back in the garage.

I took the serpentine belt off and inspected the dynamo, vacuum pump, AC, and servo. All spin good with no irregularities.

Here are two videos of the engine running with the serpentine belt off (again, LOUD noise warning!).



Now, have anyone here experienced something similar before? Anyone have a clue as of what it might be?