[Escher]

In the cars without an external filter, there is no need to replace the internal one, as it is just a screen. Most the time this gets replaced and the pan leaks.

Thank you, @nipper ! This point bears repeating.

And thanks @Brucey for the original write-up!

On my 1998 Legacy GT, the previous owner changed the ATF fluid and “filter” (screen and gasket). By the time I bought the vehicle from him, a lot of the fluid had leaked back out, and transmission shifted rather poorly. Doh!

After letting the poor car sit for an eternity, I am now finally getting to address this issue. I’ll have to make sure to drop the pan and re-seal to keep the ATF inside this time.

PS: My 1998 does indeed not have an external, canister-type ATF filter. So I bought one for naught.