My dad changed his tranny fluid on his commander.. it`s a special transmission, made by Mercedes.. and you can only change the fluid by the VIN number =\.
Anyway, for my 04 3.9 when do i have to change it ? =]
i heard 70k miles is the time to change a trans fluid.
and yes 40 anniversary sixers came with 3.9L
Resvon, get a shift kit. idk what it is, but i heard it's worth it's price