Changing ATF, how to calculate percentage

[Turbo_Bimmer]

Anyone knows how to calculate the percentage of new fluid that will be in my transmission after 3 fluid changes?

I did my first change including dropping the pan, that took 5.3L.
I figure that my next change without dropping the pan will replace 4L, and the third one another 4L.

What would be my percentage of new fluid after the 1st, 2nd, and 3rd changes, assuming the transmission holds 9.5L with the cooler?

Ok, I will do the easiest one. After the first change, the percentage of new fluid will be 56%


Here are the data I collected:

Draining the pan: 3.6L
Let it drain overnight (12hrs) 0.46L
What was left in the pan: 1.3L

[JCL]

Well, you need to drop the pan and replace the filter each time.

Just assume you are doing 50% each time. After one change there is 50% old fluid. Then you do it again and there is 25% remaining, if you run it long enough to mix completely. Do it again and there is 12% old fluid remaining.