It was easy. I just reversed the flow of the flux capacitor, as suggested by Insomniak.
I didn't bother to change the jumper setting from "slave" when I took the WD out of my old computer. And the Seagate system drive was set to "cable select" out of the box. Maybe with some drives those jumper settings wouldn't matter, but it sure did with these. So I just set both jumper settings to "cable select" and everything checked out fine.