While driving a 1969 autostick I find that the car sometimes will not go into low gear. The previous owner said that this sometimes happens, especially when it is cold out. "Cold" in Northern Calif., is I suppose below 50 degrees Fahrenheit.
After revving the car and having no effect, putting it back in neutral and trying again in low and then a third time in low, it sprang into action and we were on our way.
This did not seem to happen in 1st, although I have barely driven the car so it might.