I have opted to do several consecutive drain and fills vs the radiator trans. fluid line flush. I have to put my V90 on jackstands to remove the pvc belly pan and access the filter anyway so I figure I can slide another 2' over and unscrew the trans. pan drain plug. I did the 3rd drain and fill since I owned it...probably 15K now. I do not use synthetic. I know some of you guys rave about it but to tell you the truth, at $8/qt. you are probably convincing yourselves of it's value. Anyway, I used good old Pennzoil DexronIII/Mercon from Pep Boys: I drained out about 3.5 quarts of warm existing fluid and carefully refilled the same amount. The old fluid was brownish red but with no discernible burnt odor. The trans. shifts smoothly and quietly and the somewhat harsh kickdown from 2nd to 1st at the 20mph mark is almost unnoticeable now.

I think it a fairly prudent and reasonably affordable practice to continue this regimen with every 3rd oil change or so. It works fine and is just an extended duty of your oil change routine. I use the Motiva pump extractor on my 94 940 NA as there is no need to put it on jackstands for an oil change. I used the WalMart Super Tech trans fluid the last time I did that and it shifts perfectly with 110K on it. I suspect the SuperTech trans fluid is Exxon/Mobil near me so I believe it is just fine too. At 4x's the cost, I cannot justify the synthetic.
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94 940 108K ,98 V90 9109K