Transmission issues

I have a 1962 Ford Falcon. The two speed automatic is having trouble going into 2nd gear. I have to drive the car for 10 min before it shifts into second gear. I checked all hose line connections for vacume leaks and did not find any issues. When the car warms up the transmission shifts fine but when it cools down its back to staying in 1st gear. Anyone know what is causing this problem?

 

just for grins drop the pan and check the filter

 

Shift modulator is junk. Some of them are adjustable sometimes too.

 

I had a '66 Olds Jetstar 88 that did the same thing. It had to warm up before shifting into forward gears. Trans shop said it was old tired seals.

 

I will take a look at the transfilter for a start then adjust the shift modulator. If that dont work I'm getting another transmission.