You don't have to disassemble the steering column, but you should remove it from the car. Just remove the two bolt holding the column to the dash, and the 4 (3?) bolts holding the firewall bracket that supports the lower end of the column. Disconnect the turn signal harness, then remove the bolt and nut holding the coupling to the steering box (later models use a roll pin), and pull the column out. Much easier to mess with the coupling when the whole column is out of the car. Actually, I've never done it any other way.