HL-5370DW Printer Jams the first time I try to duplex print.

Whenever I try to print double sided after the printer has been in standby for a while the first page will come out, then feed back in part way, and then I get an error message.

Once I open the back cover and then shut it, 90% of the time the job will start again and it will print without a problem. The other 10% of the time I have to do the same process again and again and eventually it will work.

There is nothing ever in the rollers, or any debris in the way. It's pretty clean in there.

I'm not afraid of taking it apart to find the culprit. I can't seem to find the answer in the 5370DW service manual.

Anyone have any ideas? Between this issue and the fact that it keeps losing connection with the network it might be time for an upgrade.

Thanks in advance.