AJS,
I'm going to guess on this as a '35 is way out of my league. All the later trucks had a steering shaft that was 'one piece' with the worm gear...it was a single, factory piece.
To get the shaft out, you have to almost completely disassemble the steering box. It would be easier to just remove the box intact from the frame. Does this make sense.
I have linked a picture of a '38 steering box. The picture says "car" but the page heading says "truck". Maybe it will give some some ideas. Good luck.
http://chevy.oldcarmanualproject.com/shop/1938/38csm212.htmlStuart