Too much transmission fluid consequences?

Hmmm, interesting. Same as the new Amsoil ATF, it claims being appropriate for the new Dexron spec *and* WS

 

The problem is, what's the worst that could happen if the fluid isn't appropriate? You could destroy the transaxle and it won't be covered by warranty.

There's no evidence that the official Toyota WS fluid is bad, so I think paying a few extra bucks for the official stuff is worth it. You'll only be buying a few quarts over the life of the car anyway.

 

Yep, as far as we know! The problem I have is that Toyota did not make a special fluid for the Prius. This the same fluid they use in all the vehicles as far as I know. That means it is a compromise between lubrication and clutch/band compounds. It appears all the Prius needs is a first class lubricant that does not dissolve industrial wire coatings. Many Toyota's over the years have used dextron fluid with great results as well as some Dodges, Fords, and many other brands. It is possible that the WS is some super fluid that protects the Prius gear box. However, I do not believe that and have to wonder if Mobil 1 Transmission fluid would be better.