at what mileage did you guys change the transmission fluid? thanks

 

I’m not touching this one...

 

It should be changed at 60k

 

The issue is that many dealers refuse to touch the transmission fluid because Lexus states that the fluid is lifetime. You have to then find an independent mechanic who will do the job for you.

 

I work at a Lexus dealership and they did a drain and fill for me. There is no such thing as "lifetime" fluid, it will break down and get contaminated and lose effectiveness. Transmission fluid drain and fill is much cheaper than a transmission rebuild. :P

 

I tried to get one at the dealer and they just refused. I was going to find a mechanic to do it for me but instead decided to get a car without a transmission

 

Major oof. But yeah I don't understand why they stand by that "lifetime" fluid claim. It's just common sense that an oil, when put through heat cycles, is going to lose its viscosity over time.

 

When I was replacing AT fluid in my Corolla, (and after dropping the pan first, and adding the same volume of new fluid) I simply used the AT ---> radiator coolant line to drain the rest of the old fluid, while making sure I add the same volume back. Did it 2-3 times and got almost brand new pinkish-red looking AT fluid.
I would assume that IS should have some kind of AT cooling lines that run to the AT radiator too...so, it should not be impossible to do..

ps. My corolla was at 90k miles when I did the flush and after that it started shifting a little bit quicker. The change was noticeable.

 

I did mine at 40k miles. and will do it again every 30k miles.

No noticeable difference before and after change of transmission fluid

 

Always a tough choice with auto trans. The fluid exchange on a 10 quart transmission is so expensive (if you go to a shop, i've seen $300-$450 quotes) that by the time you've done 3-4 changes during a car's lifetime, you've exceeded the cost of a used transmission once you've reached that 200,000 miles you'd likely experience a failure at. And lets face it, not many here will be keeping their ISs until 200k.

I'm a big fan of changing fluids though, especially on auto trans. Just saying if you do the math, it's a hard decision to make.

The Aisin 8AT seems to be pretty robust as it came with the Lexus LS first... so i think it's sticking around for the long haul regardless of whether you change the fluid or not. And since they're so reliable, they're cheap on the used market since there's little demand for them.

 

Imho flushing it every 80k-100k miles should be enough if that AT is used in normal operating conditions. Doing it more often will produce no difference (other than making your wallet lighter).