About to renew the ATF in my 4R75-E currently running in my 2005 E350 w/5.4 gasoline engine. its history to-date:

1) Rebuilt @140,500 miles; new pan filter and external filter installed at that time too.
2) @ 195100 miles Mark K's full fluid flush/renew, external filter replaced NAPA 1-8721), did not replace the in-panfilter. Blackstone Labs report comes back as still a very healthy fluid despite its extended renewal interval.
3) @ another fluid flush/renew upcoming in a few months but want to ask a few questions anyway..........

-When exchanging the fluid by allowing the transmission to pump the existing fluid into my catch container I believe its not necessary to replace the in-pan or the external filter I've installed. This sample will be submitted to Blackstone Labs for analysis. Any thoughts or opinions on that?

-Previously I began by draining the pan through a drain plug during the re-build, replenished up to 5 qts before starting the engine and proceeding with the fluid pushed out by the transmission, Once I'm ready to start the engine proceeding with the flush/renew without that first drain/refill step----any ideas or suggestions there?

FWIW here's a thread about my previous experience with Mark K's procedure on both a 4R70W and this 4R75E too: https://www.ford-trucks.com/forums/1...ans-flush.html

TIA !

 

The internal filter is good for the life of the transmission. If there is enough debris in the filter to make a difference, the transmission has already failed. I don't know anything about the external filter you added.

Either way gets the same results. It doesn't matter.

 

^^^Pretty much as I guessed Mark, thanks once again for your valuable input of experience!