Aisin WS vs. Toyota WS

[LavaRand]

There's lots of threads about whether to use WS transmission fluid or some other alternative like MaxLife.

Since I'll be doing only a partial fill I'm partial (heh) to sticking with the exact same fluid not to mix fluids.

Toyota WS fluid is a little expensive and hard to find online but Aisin "WS" fluid "specially formulated for foreign cars designed for WS fluid" is pretty easy to get. Is this truly identical to Toyota WS fluid? Or is it not, and I may as well use Maxlife afterall?

 

[Kalle.J]

Should be the same as Toyota WS, Mobil ATF WS or close enough.
RAVENOL T-WS is another one.

 

[Shel_B]

There's lots of threads about whether to use WS transmission fluid or some other alternative like MaxLife.

Since I'll be doing only a partial fill I'm partial (heh) to sticking with the exact same fluid not to mix fluids.

Toyota WS fluid is a little expensive and hard to find online but Aisin "WS" fluid "specially formulated for foreign cars designed for WS fluid" is pretty easy to get. Is this truly identical to Toyota WS fluid? Or is it not, and I may as well use Maxlife afterall?

Some time ago, the differences between the two fluids were posted on this board. My recollection is that there were differences. The difference I recall (no guarantee of the quality of my memory) most clearly is their viscosity. The Aisin was a thicker fluid.

Here's one link with the included preamble

If your question is have there been VOAs done on both ATFs to compare and definitively say they are identical, I've not seen them. However, the two have been discussed before and linked is one of the most recent. A good reference to the topic in my opinion. I'd just add, as I noted in that thread, simply because Aisin labels as single use WS, one can't assume it is identical to Toyota WS. Otoh, doesn't mean it's not perfectly fine to use in WS application either.

https://bobistheoilguy.com/forums/threads/toyota-ws-replacement.309183/
Here's another discussion that might interest you:

https://priuschat.com/threads/testing-toyota-ws-vs-redline-d6-vs-aisin-ws.214069/