Dell 1815DN Will not Duplex print with out jamming.

My Dell 1815DN laser printer will print single side just fine, but when i try to Duple print the duplexer always jams. It will print ones side pulls the sheet back in prints the other side and as it pulls the nexts sheet of paper in from the paper tray and starts printing it jams with the sheet that just finished printing. Always end up with a sheet jamed in the tray with another sheet partailly printed still in the fuser.

There is no stray pieces of paper in the Duplex tray, i cleaned all the dust out of it as well. The Fuser and pressure roller are both nearly new with less than 2000 pages printed, but just to make sure I swapped my spare Fuser ( approx 10k pages printed on the spare fuser) in to see if it made a differencce, same results. 

I was in the middle of a rather large Print Job (600page/ 300 sheets) just when i started having the issues about 500 pages in. now no mater what i try it just refuses to duplex print. I have a new pick up roller ordered that should arrive tomorrow, hoping that perhaps that will fix it.

The pickup roller did not fix it, could the duplexer motor have failed?