I own a mazda 3 06 hatchback sport 2.3l. I bought this car about a year ago with 145k, currently at 152k, did a oil change soon after, and have been curious on the whole tranny fluid change thing. The thing I'm referring to is not replacing it itself but if the previous owner never changed the fluid would it hurt me to change it now. It's still reddish which I understand to be good. (my knowledge includes yt videos, my slightly mechanical friend, and alot of forum reading). I've heard that the old deposits may break free and can cause cloggings and issues. Now let's say you guys(generalizing not being sexist, haha) say I shouldn't because of deposits. Don't take this next part to seriously if it sounds really dumb, I'm just trying to figure out what's possible and what's not. What if I, or had someone else, probably not me, but myb a family member could help, removed the transmissions or wherever the fluid is kept, and kind of cleaned it out after removing the old fluid and before putting in the new, so if there is deposits they wouldn't clog anything, or is it better to flush is, replace filters and check for clogs in places, if that's even how it works, and leave it on the whole time. Again my knowledge is limited, so might just be random talk.