drainig tranny fluid droping n cleaning pan changing filter would it harm tranny on 2002 Ford Explorer

tranny pan holds 4 quarts not all fluid would be change would this harm tranny it has 148000. there is no dipstick the only way to add fluid is by the pan

1 answer
there is a fluid plug on passengers side of trans and it has an inner insert which is the full level. if you would like to call me il explain. greg 714-633-8219