1955-62 1/2 ton center sections will bolt right in 1940-54 1/2 ton axle housings.
As for pulling the torque tube, you need to pull the back cover, remove the lock bolt from the carrier that locks the spider gear shaft in place, then pull spider gear shaft. Then you push inward on each axle until the C clip falls off the inner end of the axle, then pull the axles out. Then undo the 10 mounting bolts and remove.