I have a '93 240 that was recently stuck in a big puddle of water
( http://www.brickboard.com/RWD/volvo/1391078/220/240/260/280/emergency_stalled_big_puddle.html ). One of the things I did to recover the car was a transmission fluid flush. About a week (~150 miles of driving) later the car wouldn't shift out of first. After driving around a parking lot for 5 minutes, everything was 'fine' and the car shifted smoothly.

Then I went on 2 weeks of Christmas vacation where I didn't think about cars at all.

I'm now back and experiencing the same problem. I did a 2nd trans flush (using 12 quarts and the cooler line method) and noticed that the fluid STILL seems a little cloudy. I'm not sure how clear it was after the first flush because I did it at night on the street. I also have to admit that it was previously overfilled by at least 1/2 quart and driven that way for a week or so.

Is it possible that the cooler line method didn't flush all the water out?
Is there a leak between the engine coolant and the transmission (although you could think that pressure would push the oil into the coolant instead of vice versa)? Any other ideas?