Technical Wierd Cruise-A-Matic trans issue

1964 Ford Fairlane, 260 V-8, 2 speed Cruise-A-Matic. When I first run it cold or warmed up it takes about a mile or more before it will up shift. After that it shifts perfectly the rest of the day. Put 250 freeway miles on the car this weekend with no hic ups but that first up shift. I'm planning on selling this car and would like to solve this issue before hand. Thanks in advance!

 

Change the filter.

 

If it has a vacuum modulator it might be that either the vacuum is low or the modulator is sticking when cold.

 

A can of Trans-X will fix it.

 

Dried out and cracked lip seals on the servo.
You'll find more issues inside, guaranteed.

 

So I'm not into snake oil remedies but I dumped a pint of Trans X in it and 500 miles later it's mended.