goodvibe wrote:Use the recommended fluid. Toyota or GM. I wouldn't use the Amsoil. Their 'compatible with' disclaimer doesn't involve any certified testing in the application. There's no universal ATF now a days. Mobil 1 for instance specifically says not to use their universal synth ATF in this app. Different tranny's need different friction levels and viscosity's to work properly. ATF isn't filtered and tranny operation produces lots of insolubles from pad wear. Acid neutralization also wears out over time so you're better off with more frequent changes and don't need synth. The pads and bands need a very specific set of conditions to work properly and less friction would be a bad thing for instance. Amsoil may or may not be optimum for this tranny but there's no way to tell from their specs and seat of the pants can be misleading. Either firmer or smoother shifting than stock could be a bad thing for longevity. Same for additives. You don't want to change the character of the stock fluid that the tranny was designed with. It's an integral part of it's correct operation and not like motor oil where less friction is always good and a wide range of visc. work fine.
I use Amsoil in my '04 model. I dump and refill (about three qts) every 10,000 mi oil change, its been done a total of 5 times so far, first three right after 50,000 when I bought the car, about a week apart, and then at 60K and at 70K. It works just fine, cannot tell a difference.
Its not like Toyota makes this fluid themselves, someone makes it for them. Amsoil has testing labs and enough knowledge to know if the fluid is compatible/safe to use in it.
You could say the same thing about About any car, that Amsoil is not the correct fluid and might cause problems, thus what you are really saying is that no one should ever use anything but the fluid sold by the dealer for that car, no matter what kind of car it is.
Charles