I've changed the transmission fluid to Mobil 1 synthetic ATF since it's a pretty good fluid. It doesn't shift smoothly anymore. After doing more research I noticed that Toyota's own ATF is recommended. I'm going to change it out but to what? This is for a 93 Lexus GS300 with 75k miles. It says to use T-II but they only have T-IV now. Is using this better than using Amsoil ATF?
Thanks