I just did this on my 940 and here is a real easy procedure:

Supplies needed: -oil drain pan to fit under transmission (6 qts)

-Long funnel with narrow tube to refill transmission

-5 foot long clear vinyl tubing, 1/2 inch inner diameter

-three one-gallon milk jugs, each marked with 1 qt lines on the side with permanent marker

-about 10 quarts of tranny fluid (I use Castrol Syntex Dexron)

-wife or friend to help.

Steps:

a. Drain the transmission pan through the pan bolt. If your fluid is really dirty or hasn't been maintained in years, STOP, get a new pan gasket at the dealer, remove the pan and clean it, and reinstall. Refill with the proper quantity of fresh fluid.

b. Disconnect the top oil cooler line (the return line) at the radiator. Use Liquid Wrench, a backup wrench and don't bend anything.

c. Move the metal tubing out of the way. Screw the vinyl tubing onto the flare fitting coming out of the radiator. Put the other end in a milk jug on the floor.

d. Start the engine and let it idle. Fluid will start coming out of the vinyl into the milk jug.

e. As the fluid is pumped slowly into the milk jug (around 1 gallon in two minutes) refill the transmission through the funnel with the same quantity.

f. When you fill one jug, move the tubing end quickly to another. Keep refilling.

g. Continue this process until you have about two quarts of new fluid left. Stop the engine, let the remainder drain from the tube, then remove and reconnect the cooler line. Don't over-torque. Measure the pan quantity and refill to the correct level. Warm up the engine and transmission and recheck the level. If you put too much in, drain a little through the pan bolt. Dispose of the old fluid properly.

This procedure will flush most (not all) of the old fluid through the torque converter and replace it with new fluid and give your transmission a new lease on life.