How do I change the auto trans. fluid on an '06 Sonata?
 

Does the pan have to come off. Is there a filter and drain plug?

Remove the large drain plug from bottom of trans case (need 15/16 or 24mm).

Let drain, install plug (find the thin seal washer and make sure it get put back)

Add 4qt of HYUNDA/KIA 00232-19012 SP-III ATF.. let run and get real hot, inspect level with shifter in "N", add ATF slowly to bring level just to bottom of HOT zone on dipstick, test drive, verify oil level.

https://www.hyundaiforum.com/forum/a...1&d=1288138042

I read somewhere in this forum that this procedure will only partly remove the ATF and that to do it properly, one must flush out the connections at the radiator(?) Is this true

That is true of all automatic transmissions, yes.

Sbr711, is the procedure the same for the '11 Sonata (do they still have a drain plug)?

Nevermind. Asked my dealer today as I was in getting maintenance parts, and he says they do still have the drain plug.