It is probably best to remove the entire unit from the steering column. although you may be able to partially pull the tube back to get working room.
If you have a non adjustable column with a one piece stator tube;
Disconnect the wires coming from the front end of the steering box, tape them into a small bundle, & attach a long, stout retrieval wire or string to the wires.
Loosen or remove the olive nut on the front of the steering box & pull the whole stator tube assembly, with wires, out from the steering wheel end. If the wire gob is too big to fit through the hole you may need to cut any connectors off. The string is to pull the wires back through the tube when you put things back together. Put a drip pan under the steering box, & temporarily plug the hole to preven all the lube from running out.
If you have an adjustable column which has a two piece stator tube;
There are some set screws on the back side of the steering wheel which need to be loosened. Pull the top part of the tube, which is about 8" long, with turn signal assembly back or remove. the lower end of the tube will stay in place. The upper & lower tubes telescope together & have a somewhat crude spline arrangenent to prevent rotation. The wires still have to be fished through the tube. Be sure that the top & bottom tubes are properly engaged when you put things back together. Just remember that with either type, the lower tube should only stick out of the box about 1/4 inch.
I think that tahoehealey & bighealy have both done the adjustable type column. Maybe they can give some good info.
D