What steering coupler do I need?

This isn't a hard job. Just a pain lulling the steering column back for access. Mark the position for everything before you diassemble. Pay attention to how the coupler comes apart. The hard part is getting that tin seal retainer to stay in place. Patience is your friend.
I'm wondering what started all this. Play in the steering? Could be the box needs adjusting. Check by moving the steering wheel slightly back, and forth. If the column rotates, but not the coupler, there's your problem. If the column, and coupler rotate together, it means the issue is the steering box.