Firstly hello from sunny Cornwall in the UK
I have a 1947 desoto custom with a fluid drive transmission in really enjoying driving this car around
But I'm having trouble with my gearbox
In high range it is slow to change up I drive it as normal then when I want it to change up I have to lift off the gas and waiting at least ten seconds for the box to change up
I have checked and topped up the oil level
anybody have any ideas as to what's wrong with it
thanks in advance