Originally Posted By: The Critic
Originally Posted By: Or

Originally Posted By: mrdctaylor
So do most people hate the Toyota ATF WS? I've always tended to use factory fill ATF. I use Hyundai SPIII on my Santa Fe and have had good luck so far. I had planned to stick with ATF WS.
I think there are quite a lot of people who are very disappointed that Toyota has made promises about WS that it can't deliver. As a semi-synthetic fluid, it works and is on par with the general field. It's not a "lifetime" fill and high mileage owners, 2nd owners, are inheriting problems from the "just get it out of the warranty period" and "lower the TCO for accounting purposes" approach.
It's not
per se a horrible fluid. But it's in the middle of a serious slide in engineering quality standards and product quality on behalf of Toyota. The part of the introduction of it that was coupled to goosing the CAFE numbers are unclear, also. Toyota engineers have mentioned in published engineering papers the purpose was to increase mileage - a lower viscosity fluid that could goose mpg a teeny % - at the expense of the buyer's hardware but to the benefit of Toyota's penalties under CAFE standards.
I have yet to see any "proof" of issues with WS being a lifetime fill. Most Toyotas have had WS as lifetime fill since about 2003-2004. We have not seen/heard of the transmissions failing in mass quantities for the 2nd and 3rd owners.
What you see in the fluid often has little correlation to its serviceability. Shops use this scare tactic (fluid color/appearance) to sell more services.
My 2003 and 2004 Toyotas have T-IV as a lifetime fill. The fluid is a dark reddish brown in both vehicles and has been that color for a very long time without visible change. I was told by Jiffy-Lube the ATF was dark and smelled and needed to be changed very soon or something bad might happen. That was 150k miles ago.