Jams on duplex only , single side pages are feeding fine as per customer . Tried running a single 2-sided page through the ADF as a duplex page output , hoping to see a single duplex page jam , ran about 20 of these , never jammed . Running 8 1/2 x 11 side feed , page count is 1,125,813 , duplex model number is AR-DU4 . Ran stacks of varying sizes , reported jamming occurred twice , but of course paper stopped in 4 spots on one of the jams and in 2 spots the other time . In both cases there was a page , 2nd side with about 30 to 40 percent of the image on it , other side fully fused , the partial page had arrived at the fuser , but did not feed in , as only maybe 10 mm was fused , as it had only touched the fuser , in one of the cases it was folded , registration looked normal . other page was on the outer path of the duplex unit , feeding downward , both had this paper left after jam . And in the one case paper was in the unit on top where the page feeds out and then pulls back in . Ran a 22-6 report , jam codes indicated were mostly APPD1_S (17 of 20) , not sure if these were indicating a cause or just showing the result of the paper stopping , as the page in the outer left path of the duplex unit was sitting on the associated sensor flag . Tested that sensor with the SP mode for that , seemed fine . Pulled the cover on the duplex unit rear side , test ran the 2 motors , on/off fine . Saw a 1-way bearing on 1 of the gears near the motors , worked it a bit , seemed to catch consistently . I don't see this unit much , have the service manuals for the machine and the duplex unit . Any ideas on what may need to be done or if there are any tech bulletins relating to this problem ? Thanks in advance , Ark .