This x100! The absolute first weekend I have my 940 home, did a tranny flush and it cured a bunch of ills. All you need is a piece of 3/8" tubing, a drain pan, 3+ gallons of cheap ATF and an empty 1 gal milk jug...and I think three different open-end wrenches.

The coolant contamination is a very real possibility and if you see any signs of it...start looking for used tranny. I suggest a pre-emptive radiator change to anyone who has an original radiator in a car this old...if the name on the radiator is blackstone, it is likely original. If the internal transmission cooler int he radiator springs a leak, you are in for a world of hurt.

Which leads to the orad of things that can kill a 240...pretty much not that many things but one of the others is a blown radiator hose or heater hose so consider replacing those at the same time.