Start from scratch...
Disconnect the drag link.
Turn the wheel all the way to one direction.
Turn it all the way to the other direction, counting the turns.
Come back exactly half the number of turns.
Is the wheel centered? If not, the problem is somewhere between the steering box internals and the steering wheel.
If the steering wheel is centered, look at the pitman arm. Compare it's position to that of another JK when its wheels are straight. The shaft could be twisted, and still look good.
2008 Unlimited Rubicon Automatic