I have an auto too, and I flush the tranny fluid once a year, and only use the Toyota Type T-4 fluid I think. I think that's what it is. Someone please correct me if I'm wrong.SupraLB said:At what mileage intervals do you need to replace the tranny fluid? I have 41k miles on the automatic tranny, but I just bought the car so I do not know if the previous owner replaced it.