3 Speed Push Button Auto

hey guys i know this is going to sound stupid, because its a pretty simple question but i have a 64 valiant with the 3 speed push auto and, and i was wondering what type of transmission fluid to use with it.

some people said atf 3 or 4 and some say dextron and i have no clue.

my transmission worked fairly well before, but then my dad added some regular atf and its started slipping, were going to drop the pan and change the filter and stuff but i want to make sure we get the right stuff for it, (even if it is the right stuff we put in the old already in there was pretty nasty so were going to do this anyway.)

sry i know this should be pretty simple and straight forward but im new to plymouths (been chevy tell i found this car)
Author: admin