In automatic transmissions, is the oil filtered before entering the hydraulic lines?

I am thinking about changing some pieces of my transmission that broke into pieces inside the transmission. Are there any chances that the hydraulic lines are blocked by these pieces, or do they have their own fluid? The pieces that broke were the planet gears, and planet carriers. I am also going to change the friction band and some clutches. It is a transmission from a 1999 nissan quest.