Hello. My Toyota automatic transmission is very smooth and confortable, but also very very lazy. The changes are slow and the torque converter slips way too much. This is a common problem in these kind of Toyota transmission, I'm in a forum where many members solved it by fitting in a new valve body. I tried one and the results were impressive, still comfortable but much faster car, better engine braking and better fuel economy also. The problem is that I can't afford the valve body now and a friend told me to try Amsoil super shift racing oil to get better response from the transmission. The problem is that, in the Amsoil data sheet, it's stated that "AMSOIL Synthetic Super Shift® Racing Transmission Fluid is not recommended as a replacement for Ford Mercon®, GM Dexron® or Chrysler ATF+ type fluids in passenger vehicle and truck transmissions as it may cause erratic shift patterns, chattering or noise". My transmission is Toyota made, not a GM, but Toyota recommends Dexron II fluids (I'm using Dexron III now), so I think I could have problems. What do you think? As an alternative, I've thought that the new Low-viscosity ATF could also provide firmer shifts and it's Dexron-VI, so I should be fine. What I doubt is that the improvement with the low viscosity one would be noticeable.