Originally Posted by NH73
What makes WS much different than other ATF?
Nothing.
It is typical semi-synthetic LV fluid. However, with manufacturers fluids there is always a chance that manufacturer during testing realized certain issues that could be addressed with fluid and certain additives. Toyota transmissions are generally designed as "lazy." Meaning, they are purposely design to operate below its peak performance as cars are not designed for such use. I have same transmission in Sienna and Tiguan. Two different animals. In Tiguan it is programmed aggressively, in SIenna, when you shift from D to S4, and then immediately to S3, one could take a sip of coffee, light up cigaret and then something would happen. Their 8 speed is designed similar way, lazy, compared to other applications. So, fluid is appropriate for that design, that performance.
I am doing fluid next month. I will use WS (being delivered tomorrow). For me, more important is regular change as well as filter change, than whether it is WS or Maxlife. However, as I said there is always a chance that Toyota knows something that other don't. VW ATF supplier for 6 speed and 8 speed is Pentosin. Maybe that transmission behaves differently in combination with VW engines and drivetrain in general. So VW wants certain type. Who knows? Why risking? Also, why mixing fluids? I will do fluid drop and replace, with no flush.