Originally Posted by boboridesthefa
How much fluid will I loose when I drain the pan to drop it and what type of fluid should I replace it with and how often should it be changed?
About 6-7 quarts.
Now fluid type for a 4R100 is a debated item.... your dipstick and manual will state mercon only. But Ford came out with a TSB in 2006 saying Mercon V now superseeds Mercon and to use that. Some claim you will run into issues running Mercon V (which ford originally said not to use in these trucks)...others (myself included) don't agree. Do a search and you will find 129387912083902183 threads on it. IMHO so long as it meets specs, it is more important you service your trans regularly than what brand of fluid is in it. Personally, I am running Super Tech (yep wally world brand) Dex/Merc...works just fine.
Per your owner's manual you are supposed to change as much of the fluid as possible every 30k miles.
A quick, easy and effective way to do it in the link below:
4R100/E4OD Trans Flush Procedure - PowerStrokeNation : Ford Powerstroke Diesel Forum
I have done it to three different cars...works like a charm.