Why does my transmission whine on my 1974 cadillac after sitting overnight?

My transmission whines in the morning or after sitting about 15 hours or more. After about 1/4 to 1/2 mile everything is fine the rest of the day and evening. No whine and no problem. But the next morning same thing again, what is going on with it. It is a 1974 cadillac with 95,000 miles Fluid level is not low and there is not a bit of leaking all gaskets are perfect. DId transmission gaskets and seals 4 years ago.|||coating on trans screen/clogs up and the pumps are making that noise/change trans oil/replace the screen and add 1qt lucas transmission conditioner at the change/do not keep operating it this way/use the normal trans fluid for the other approx 3 qts/if you do nothing else at lesast add the lucas now|||change the fluid and filter. the filter could be starting to clog up.|||may be blocked oil strainer in trans pan