I have a 2006 IS350 with 98k miles. I have always changed oil & filter every 5k miles. I have never done a transmission fluid change. I took it to my mechanic and he said there is no dip-stick and he belives the tranmission fluid dosn't need to be changed because it is for lifetime of the life of the tranny. Please advise us. I looked in the owners manual and it does not talk about tranny fluid at all in the maintenence schedule. The dealer of course says it needs to be done every 30k miles. Which i belive is probably overkill.