Converter noise???

All of a sudden my car is making an incredibly ugly noise when I start it up. It sounds like the rods are ready to come through the pan. It has no rhythm to it. It's not like it's a knock or something in the valve train.
But here's the weird part. If I bring the RPM's up to say 1500 it goes away. Then after it warms up it only makes the noise in park. So that leads me to believe that it has something to do with the converter.
Here is the set up. It's a 904 with a shift kit that was built long before I bought the car 3 years ago. Last year I put in a new Hughes 2500 stall converter. Since then it's been fine but this just came on out of nowhere.
Anyone have any idea's on this?

Thanks....................Ted
Author: DemonTed