The auto on the FJC is the same unit as on the LC100 and 4Runner (V8 and V6), so it is pretty stout. I also believe the last Tundras (before the new ones 0 ran them, I think the new Tundra with the 4.7L V8 runs it too.
So all are more powerful and heavier rigs that can tow up to 7000lbs or so, and very few issues to date with the A750. I seriously doubt the FJC will do that unit damage unless you drown it.
Don't understand why they didn't fit the same config as the v6 4Runner on the auto FJC, with 2WD, fulltime 4WD in Hi and Lo and then separate center diff lock option in high and low range. Gives you the best of all worlds.
BTW: For those who don't know the A750 will lock the TQ converter when in 4Lo, so it has plenty of engine braking downhill similar to crawling along in a MT. Just slap it in 3rd, 2nd or L gears when going downhill and it locks up. Obviously it unlocks the TQ converter when you stop doing engine braking and hit the gas pedal. Very neat AT for wheeling, much improved in smarts over older 4 spds.