I didn't care for the Dorman pan. I looked at it at Advance, and walked out without it. The sealing lip didn't give me a warm, fuzzy feeling. Might be fine, but I didn't want to chance it.
I would try to change all the fluid at once. Doing a little at a time, you will end up throwing away a lot of your new fluid, would take 20+ quarts. If you can get under the car and drop the pan, you can also drain the torque converter. Job done.
Don't forget the filter, and either re-use the stock gasket or buy another Ford gasket. Those thin rubber ones that come with the filter aren't any good.
12 is usually enough. When the valve body is removed, then you need that 13th quart.
What draining the system from the cooler line does, is keep you from making a mess when removing the pan, it is mostly dry. But you do have to rig up a fitting and hose for the radiator, and run the car for 30 seconds.
A forum community dedicated to Ford Thunderbird, Mercury Cougar and Lincoln Mark owners and enthusiasts. Come join the discussion about performance, modifications, troubleshooting, maintenance, and more!