I have a 1963 Jetaway 315 4 speed Hydramatic that when it is parked for a few days the dipstick shows it is way overfull . Also when I first start it I must wait for almost a minute before it will go into any gear after a minute it works flawlessly. . I have been chasing leaks and the trans never leaks when driving or parked for 8 hours or less , After that the dipstick will show it is overfull and it leaks due to the fluid level being above the pan gasket level . I now have the pan gasket sealed and it still leaks from the dipstick tube. Did these cars leak when new when parked for several days?
+1 on checking the transmission fluid when the car is running, at operating temp, and in neutral.
Common mistake for people to check it cold and engine off. Yes, it's pints, not quarts, on the dipstick.
As for being hesitant to go into gear after sitting for many days/weeks, my 21,000 mile survivor 1961 Series 62 coupe would take about 10-15 seconds after starting the engine and putting into gear before the car moved. (This wouldn't happen just one day after a drive, however.)
It was such a great driving car that I didn't want to mess with it. I did change the fluid/filter/gasket and never saw anything leaking beyond an occasion one-or two drips of clean pink trans fluid after a drive.
If your pan is truly over-full, you need to drain it. Too-full causes problems. Other than that, check all the connections, linkages, gaskets, etc. These cars did not have any "delayed propulsion" problem when new. But, now they're 62 years old.
Heck, I was born BEFORE 1961, and I'm slow getting into gear after "starting up" in the morning as well.
I have no leaks from the main font seal of the trans and I do check thee fluid level when warmed up and idling..
it shows way overfilled when checklng cold and not running after a day or so, Once it is running and warm the level is correct.