I'd steer clear of any additives. My Previa has an A340F (same tranny as 4runr/trucks and other models) which specifies DexII. DexIII works great and should be readily available.

I used Dexron III - which is backward compatible with Dexron II. Lots cheaper than synthetic ($2.86/quart (Napa)).

By the way: the Haynes manual lists 6.3 quarts are needed for a drain-and-refill. But as I changed filter also (hence took the pan off) and all atf was also lost from radiator, hoses, etc - I needed 10 quarts (and dipstick still shows slightly low).

Does anybody happen to know the official amount when filled from completely empty?

I can report that the $25 Autozone atf filter T722 fits well and includes 2 gaskets. Not difficult, just a lot of bolts (and a lot of atf dripping).

I've found that stuff does work, at least for my 22RE. It has some worn or dried out valve stem seals and smokes under compression braking (like going down a long hill). If I put in a can of Restore, it is like the oil burning nearly vanishes. Ultimately I'll get the head rebuilt, but for now, it is easy enough to add a can of Restore with every oil change.

that stuff is amazing. you can actually feel a difference about 1,000 miles after you put it in. i wish someone would do a before and after compression test to verify if it actually evens out compression b/c it sure feels like it does. it also slows oil leaks. i'm usually against oil/fuel additives but this stuff is great. it works best in smaller 4 cylinder engines of course.