Just purchased 9/1/2019 by my son as his first car and our project car.
1993 Volvo 240 Automatic sedan Unknown mileage (Approx 150k). ODO stopped @ 90K.
Transmission model No: 03-70 1208.

Symptom: Car warms up for 5-7 minutes and then drive it, car is in D it revs to higher RPM and won’t engage 1-2.
I can engage 1-2 by shifting from D-2 and letting off gas at same time. Then car shifts fine for duration of drive. 2-3 and 3-4 shift smooth. All subsequent stops and shifts from 1-2 work. This inability to shift just occurs the first time with a ‘cold’ engine (even though I let it idle for awhile). After driving I can leave car off for a few hours and drive it without issue. In the morning or after sitting for like 7 hours the issue returns.

Fluid hits the MAX mark when HOT, so fluid is not low.

Have inspected the kickdown cable and it appears to function, I can pull it and it snaps back. I have never heard a ‘click’ though.
I drained the transmission oil pan and the fluid was the color of a dark port instead of a red wine.
I replaced just that amount from the pan. (2.5 qts)

I imagine doing a Gibbons method flush is in order to see if that will improve, worth it?

Will a pan drop and clean and filter change/clean help or just a waste of time?

Am I kidding myself and this will require the checkball change/ rebuild of the valve body?

Anything else to consider besides fluid, kickdown cable, or valve body?

Thanks for any tips.