Lexus says that it's filled with synthetic fluid and never needs to be changed.

Are most people in agreement with that?

 

We'll... it depends really. Not much miles have been logged since this car is still relatively new. I dont think many owners have changed the fluid yet (its a sealed unit, there isnt even a dipstick)

However, if you live up in the mountains, I would defiantly change it along with my 90K service at most. Its hard to believe that any lubricant can last forever.

 

I would have to say, and pretty confidently I might add, that they are correct. Synthetic fluids will last forever. I read that synthetic oil will last 15k roughly on average and that it NEVER goes bad. You only change it because it gets dirty and the additives burn off. This is in the engine where the oil contacts much higher temperatures (combustion chamber area) than the tranny could ever dream of. Synthetic ATF in trannys never get even near that temperature to burn off anything. The fluid will not destruct or (burn out) as conventional fluids do. Thus, you do not ever need to change it. Its a sealed unit for a reason.

The only situations you would ever want to change it are if the vehicle was flooded (water could get in the tranny mix with ATF), or if the unit is still operating but doing something to harm the fluid such as an abnormally large number of small metal shavings in the fluid. I wish I had a sealed unit with synthetic in it, but with the 02, I'm contemplating changing my ATF at slightly over 100K miles, it doesnt smell burnt but conventional ATF does not have the durability that synthetic does.