removing pitman arm from 97 4X4 1/2T

I need to replace the pitman arm on my 97 1/2T 4X4 but there is a crossbrace on the frame in the way. I assume I have to remove the streering box to do the job but what tricks are used to hold the steering box rigidly once it is off the frame? Also, does anyone know the socket size for the nut that holds the pitman arm to the steering box?