Today I did a drain and fill on my transmission. I used Revanol brand SP-IV RR transmission fluid that is made in Germany with my AST fluid pump to quickly fill the transmission pan.
I was under the expression that I would need about 7 quarts to fill the pan properly, but only about 3 1/4 quarts of fluid drained out of the transmission pan. Therefore, I just replaced the amount of fluid that drained out since my transmission was shifting well, so it appears to be filled correctly in that regard. Therefore, no need to waste good fluid out the level check plug.The transmission pan in my 5.0 seems to hold only about 3 1/2 quarts anyway since the fluid just flows out the fill hole when I tried to add more.
The only thing that may need be to changed on a drain and fill are the rubber o-ring gaskets on the 8mm hex drain/level
plugs. The o-rings gaskets are standard 116 sized rubber gaskets, however my drain gasket still seem good even though i replaced it anyway; so you may not really need to replace it after one use. I changed my gasket to prevent a leak. The 8mm hex fill bolt uses a metal washer which I changed as well, but it seem good as well.
The job is pretty easy as transmission fluid changes go.
Note: The shift cable is in the way of the fill bolt on the drivers side of the transmission pan. In my case it helped to hold my angled fill adapter in place while I pumped fluid into my transmission, however it can also be a problem if you use a different type of pump method.
My old fluid. It was dark reddish color, but still seem good for fluid that is 76k miles old.
New fluid. A nice light red color.
The AST fluid pump and 102 adapter I used to fill my transmission pan.
The drain bolt is the bolt in the center of the pan. The level check bolt is the bolt near the outside of the pan. I only removed the drain bolt since I knew how much fluid to replace without pulling the check bolt. However, I may still open the check bolt to make sure that my transmission is properly filled after letting the transmission fluid warm up to about 130F before I install my under body cover.
Final advice, make sure your car is level before draining the fluid or checking the level for accuracy. I used jack stands to support my Genesis.