Guess no one knows, but when I inadvertently popped mine into neutral when giving it a good boot (thought it was in manual mode) it bounced off the rev limiter before I put it back into D. (no ill effects)
So I don't think its smart enough to not go into R when it knows its going forward, or rolling quickly in N.
Come to think about it, if gears are stopped and start moving slowly, it does nothing to them. Now if you have them spinning one direction, then momentarily not only stop them but make them go other direction, there is a great chance that gear material can't hold these forces and bite off teeth - meaning it will almost certainly break. From my point of view.
I suppose so. I can't pop reverse on my vehicle if I am moving forward faster than about 10kmph. But nonetheless, I would not attempt to do it without being 110% sure there is counter-measure against trashing gearbox.
An auto box is basically a bunch of (wet) clutches and the slushy bit that connects in to the engine. At those speeds the clutch doesn't lock up so there is no direct drive, just the torque converter which is never a 100% locked connection. If the box were to somehow manage to get into reverse my guess is the torque converter "inverts" and while you get some braking effect, it shouldn't break anything. There's no physical connection to break.
That said, I wouldn't really want to try it and the car should refuse to go to reverse while driving forwards. You can shift to neutral at will.
On my old 96 Camry I accidentally put it in reverse while slowing to a stop light. Was moving at about 25 mph, my elbow hit the button on the side to engage gear shifting at the perfect angle to depress the switch as well as move the shifter forward.
The car just shut off. Came to a quick stop and the car turned itself off. I started it back up and it drove fine, about 2 years later the transmission had a catastrophic failure. Who knows if they were related.
I believe that over 8mph if you shift into R it does nothing at all. The TCM knows it shouldn't be going into R. The screen will show R, but the car will be in drive and will never go into R. There are some people on YouTube that did this to prove it. Idk if I'd be that willing to purposefully do it... Lol but you're tranny will be perfectly fine.