Classic/Antique Car Repair: 67 Ford F100 gears lock up, hurst shifters, ford f100

Question
Driving my recently acquired 67 Ford pickup with "3 on the tree," the gears stuck 3 different times (twice in first and once in neutral). It always happened while trying to move between gears. Each time I had to get out, lift the hood, and vigorously wiggle the shifters rods by the steering box. I guess each time, it was the top (first) rod that was stuck. I would appreciate your ideas about a diagnosis as well as possible fixes (even temporary fix so I can get home safely).  

Thank you.

Jason

Answer
The problem is a common one with vehicles with the column mounted shifters. The shift forks at the bottom of the column wear as well as the shift tube. Many folks who ran into this problem converted to one of the floor shifters available at auto parts stores instead of pulling the column apart and replacing the parts. This was a big boost for Hurst Shifters sales. If the rig is a nice origional truck and you want to keep it stock, then fix the column shifter by replacing the shift levers and the tube.
Brad