There is one subtle difference between automatic transmissions and manual ones and that is the manual one will allow a shift into a lower gear even when engine damage is likely.
An automatic one will not, and will hold the current gear until car speed falls within shifting range.
Yeah, newer ones can be too smart for your own good (but not theirs) - older ones had no problem with you slamming it into reverse or park at freeway speeds - ask me how I know!
I am reminded of a friend who changed his steering wheel plastic trim, in the process he bumped the wheel position sensor out of calibration. No worries, trigger a recalibration. Uh oh, won't recalibrate.
This of course meant the entire cars safety and stability control systems, ABS and traction control were all disabled. It drove like a tank.
The fix, obviously, was to replace the brake booster primer pump (hybrid car). It had worn enough to no longer recalibrate. Still perfectly functional, and would have kept working for a long time, bit it wouldn't quite meet the factory expected parameters so it failed it's test.
According to the other guy that founded the Range Rover forum I run, in the 1990s when they were getting P38s as traffic cars the training for "really really stop right now" was to throw it into reverse at 70mph and plant the throttle.
It appears that ZF 4HP20/4HP22 gearboxes can do this an unlimited number of times without apparently being damaged, but I'm not trying it on either of mine.
I have always wanted to try that! I'm not going to try it on any car I own either. It is all just super high risk, and I just don't have a spare car laying around that has the beans to pull that off.
An automatic one will not, and will hold the current gear until car speed falls within shifting range.
Ask me how I know :)