If it is hooked up to the trans right, check it where it connects to the speedo itself. The majority of cables are just "plugged" into the back and can slip out if you tug on them hard enough. You may have worked it loose when you reran your cable. I did with mine.
Its a rather stupid design. Mine came loose, and flung grease all over the back of my dashboard. I didn't even manhandle the cable that much, just disconnected it once and let it hang while I did a engine swap.
Wes
