Backing up Andy here...

My 940 had never been flushed when I got it at 133k mi, and the fluid was dirty (brownish and turbid, but no burned smell). I drained the pan via the plug, and put in 2 qts of fresh ATF to bring the level back up. Started the flush process, and about 11 qts later, clear, red fluid appeared. So 13 qts total. Three years and 33k mi later I did it again, and the fluid was not that dirty, but you could still tell (at about 11 qts total this time) when the new fluid appeared in the clear plastic tubing. This time I used synthetic. I plan to leave this alone for 60-70k mi.

I doubt that fresh clean ATF can dislodge dirt better than high-mileage old fluid. They are both just petroleum lubricants (hydraulic oil) that get hot and race around inside the trans. I strongly suspect that any dirtying of the new fluid in a few miles is the result of a bit of the old fluid being left behind and mixing in, not stubborn clumps of sludge suddenly coming loose.


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Bob (son's 81-244GL B21F/M46, dtr's 83-244DL B23F/M46, my 94-944 B230FD; hobbycar 77 MGB, and a few old motorcycles)