NOISE

My machine had the same problem. A service tech looked at my machine and pulled out the OPC Belt Drum Unit. The drum unit had a few issues: 1) jagged rips in it, something caused by running papers through that had staples or paperclips in them. So when the drum turns, it scrapes other parts and the machine sounds like its going to drop all its nuts and bolts--at least mine did!)! and 2) the spindles from the OPC unit has come loosened and fell off. The spindles and plastic cogs were found way at the bottom of the OPC Drum slot. This too was thought to have added to the rips in the drum.

I replaced the drum ($399 was the cheapest I could find) and the problem went away.

An expensive repair but for me it worked...