C-4 Transmission
 

I have a 65 Galaxie with a 289 and a C-4 transmission. The car will not go into park or 1st gear. If there is any pressure on the tires it won’t go into any gears. I’ve checked all the linkages and see nothing wrong. Please help

You will need to drop the trans pan and look at the link that moves a spool valve. That link is what you move when you select gear positions.
You cannot tell what is wrong inside until you look there.Let us know when you have the pan off.

You might get a filter and gasket kit so after you correct the problem you won't have to go back in there later.