Heres the skinny on something that took a long time to figure out. The Phaser 850 and 860 has an issue with the lift pins on the maintenance drawers. Over time they get notches worn in them because of the hardness of the plastic arms that lift them when the drum maintenance clutch fires and turns the drum maintenance cams. After a while, the oil roller and wiper in the maintenance drawer no longer make good contact with the drum resulting in poor cleaning of drum, paper sticking to drum and jamming, etc. You must replace the maintenance drawer, and replace the cam actuators with a new part number. Use the part number in the book, but change last two digits to 01. Heres the burn, apparantly the drum clutch builds up some kind of memory based on the wear of the lift pins, put in a new maintenance drawer, and it usually blows the drum clutch. We have made it policy to replace the drum clutch, maintenance drawer and the revised actuators all at the same time. Hope this helps, you have no idea how many maintenance drawers we replaced, then had to go back with the clutches after we got the 007.004 error.