I'm not sure what year they changed, but the old ones had what they called a ball nut and bearing type. The worm gear was a long screw and the ball nut worked kind of like the electric shifter on an Eaton 2 speed works. They had a bearing race that was machined on the shaft. The later ones were a worm and sector and everything is replaceable if you can find it. If you have the old style and it were mine, I would chuck it up in a lathe and polish the race with emery cloth. If it is a removable race, and you have one, you might have to heat the race to make it expand. I have a "green flame tip" that doesn't use oxygen. Only air. That way I don't get too hot. I certainly wouldn't take anything apart that you might ruin and then not be able to find a new one. Steering box bearings were numbers that don't cross over to any modern bearings.
