4 speed econoline

I recently picked up a '63 Econoline with the 4 speed column shift option and it shifts about as sloppy as it pleases. I'd like to rebuild the shift column but can't find any diagrams to show me what parts I'm missing from the assembly. I'm certain that parts are absent as there is seemingly no mechanism preventing a down-shift from 3rd to reverse. Any help or advice would be much appreciated.