Warm tranny?

The automatic tranny on my 69 takes a while to kick into gear....it takes off on 1st perfect but as I give it gas it seem to take a while to kick into next gear. I noticed once I drive around for a while the gears kick in smoother. Is it just a matter of truck warming up?

First thing, check the fluid level. Engine running on level ground. Don't overfill, the min and max marks are hot operating temps (about 170°F If I remember right). Filling to the full mark cold will be overfilled when warmed up which will airate the oil and make it overheat.

Next up, probably some internal seals are getting old and hard. They are not sealing up until they get warm. At this point it should be an easy rebuild without burned up parts.