860 Duplex Jam on Second Side

[kcmnj]

My 860DX just began jamming. The first side prints fine, the paper gets fully drawn back into the printer and then it jams. I have to pull the paper out of the front door to clear the jam. It then sends through a cleaning sheet, prints the first side fine again, draws the paper in and jams. Single sided print jobs print fine leading me to believe that it is not a clutch or a solenoid problem. I've searched all the forums and have not seen a similar problem listed. Anyone have any ideas?
Thanks,
Ted

 

[datchupokey]

There is a flag that hangs in the duplex path. It is accedssable by removing the side covers and then the display assembly. Turn it over and release the retention snaps and separate the pieces. The flag is visible at this time. It is usually held in place by snaps on the sensor body.