I started a thread on coolant and it seems ATF fluid started to take over, so here we are.
Member tammap posted an interesting video:
Quite an interesting video. Makes me want to stay with the Toyota WS, although I believe Toyota owns Aisin which builds the transmissions. They have their own Synthetic ATF 0WS fluid. https://aisinaftermarket.com/assets/...22f41d810e.pdf
I do find the Idemitsu ATF interesting. They recommend their TLS SV for the type WS for my ES350, and TLS for my 2005 Corolla.
A few use Maxlife. I did go to the Valvoline site: Valvoline shows MaxLife to replace Lexus JWS 3309, Toyota D-II, D-III,T-III, T, WS.

 

I've had great results with Amsoil in my toyota vehicles. Definitely smoother shifting

 

I see the Amsoil sells their WS compatible ATF at about the same price as local dealership charges for their Toyota WS.
Would you happen to know at what mileage the car had, and how many miles you've put on since the change?

 

Did the first change at 40k on our 2018 highlander. Traded it for a sienna at 65k with no issues, no whining or performance issues at all like that generation is starting to see now. Did same fluid in the sienna (we bought used with 40k on it). We're about 5k in and no issues at all, but it's a CVT so tough to compare to a traditional 6 or 8 speed.

 

Thanks. CVT is totally different from conventional. CVT uses different fluid and much more frequent mandated fluid changes.

 

If we speak about 6ES - then it is eCVT, not CVT. Uses the exact same WS fluid. Very simple mechanically - essentially just splash lubricated gears. Not sensitive to quality of oil at all. Toyota does not specify oil change intervals (the same "lifetime" fill) but I would not do it more frequently than 100k-150k miles. Very simple oil change procedure too - drain through the drain plug (the full 100% capacity comes out at once) and fill through the fill plug until it starts overflowing. The only problem is that the drain plug may be corroded solid into the case - which then requires replacement of a small $50 access panel.

 

I started using Amsoil in my ES350 about 30k miles ago. No change noticed, but I have been changing fluid/filter with Idemitsu before that. My second pan drop / filter change (first was at 36k, second at 70k I think) the pan and magnets were significantly cleaner.

After changing from WS to Idemitsu / amsoil I noticed smoother shifts and less idle vibration, especially with the A/C on in the summer. I have also noticed that the fluid is not as dark when changed, WS being the darkest when first changed at 36K. car has 106k now.

There is nothing wrong with staying with WS. Most people feel more comfortable with that. IMHO servicing the transmission properly (New filter and fluid) at proper intervals is more important than fluid type. As I have discussed in previous post, the ES350 has a filter with a paper filter element not a screen. It can and will reduce fluid flow when dirty / clogged.