The coupler can be removed from inside the car- just follow your steering column down towards the firewall and you will see it has an identical connection there. The coupler is sort of a universal joint, one end attached to your steering rack, the other end to the steering column inside the car ...

I know this is a really late post but I had a similar problem, could not remove the steering shaft coupling from my leaking rack to save my life. I wound up removing the coupling from the steering wheel shaft inside the passenger compartment- there is a rubber boot that seals it off, so the inside ...