I'm sure this could be one of many things, but suddenly my first gear stopped working on my '72 three on the tree.

I accidentally flicked the shifter into gear in some quick-thinking shifting, so I feel that was the cause. It was not the usual deliberate shifting that I normally engage.

Any ideas? I checked the linkage, but don't know how to tell if that's the culprit or not.

Sorry for the rookie question. ideas?

Can't help on the solution, but I've got a good 3sp you can have if needed. I'm sure I'm not the only one.

I'd chock the wheels, put it in neutral, disconnect the linkage at the transmission, and see if you can work the levers through the gear ranges. If not, I'd say bad trans. If it shifts fine, look at your linkage.

Column shifter or floor?

Those column linkages can be a pain, my guess is that you'll find an issue there. Follow Frank's advice, that'll tell you for sure if it's the linkage or the tranny.

...and it's on the column

Sounds like a linkage issue. Follow Frank' s advice blocking the wheels and get underneath and you might remove the linkage from the arms at transmission and make sure both are in neutral and then shifter in neutral as well. I think there is a hole in both linkages at the base of the column to insert a pin for neutral to keep them from moving. Reinstall the linkages in the arms at the trans.

Those damn column sleeves are usually the weak point if youve never serviced them before. Not hard to fix, but so very time consuming to pull everything apart and put it back together. Of course, last time I did one was 12 years ago in a barracks parking lot, in NC, with 95*+ temps so maybe that's why it seemed so difficult.