Knocking noise????
 

I have a 2000 7.3. When its just idling it has a loud knocking at the back of the motor. When I just tap the gas it goes away completely. Havent ran it out of oil or anything. Thought it might be the flywheel but cant see any cracks. Somebody just give me option to look at!! It only has 175,000 miles.:scare2:

Sounds like a loose or cracked flywheel to me too......or torque converter to flywheel loose