I would do a flush using the engine's power. Things keep changing, like which cooling hose is the one that comes from the tranny pump? A short engine crank should solve that.

Get a tranny funnel from the autoparts store, they have a really long flexible neck. It just takes longer to pour 2 new quarts of 3309 in than it does to pump out 2 quarts. Try to get the tranny warm, not hot, before the flush. You will need at least 10 quarts of ATF.

Check the fluid level twice after the flush. Once right away using the cold side of the dipstick and once after driving 15 minutes on the hot side.

Do not pump out ATF 'until bubbles appear in the clear tubing'. Just stop after 2 quarts are pumped out. Don't want to introduce air to the pump.

--
My name is Klaus and I am a V♂lv♂holic

I've done a fluid replacement (not a "power flush") on our 850 and a series of drain/refills on the '01 S40.

I should have done the replacement on the S40. I feel like I've thrown a lot of money away trying to change all the fluid only 2 quarts at a time. I've now done about 4 or 5 drain/refills and the fluid still looks dirty - better, but still dirty. The reality is that it is dirty considering you are mixing 2 quarts clean with about 8 quarts dirty with each drain/refill.

The 850 fluid still looks good after the replacement. What I did was remove the return line at the radiator and have a helper start/stop the engine to pump out all the dirty fluid.

Hope that makes sense.