I finally got my Seagate Expansion to spin up and down by changing the spin down settings on the drive with seagate settings software. The default setting is never spin down which I suspect is why the router spindown command will not work. It works perfectly now.
You can get the setting software from Seagate here
http://www.seagate.com/support/external-hard-drives/desktop-hard-drives/expansion-desktop/
You can get the setting software from Seagate here
http://www.seagate.com/support/external-hard-drives/desktop-hard-drives/expansion-desktop/