Per opnspaces
“ I have no idea if it would work. But if the engine quits you might try shifting the automatic transmission down to a lower gear. Worst case nothing happens as the transmission is freewheeling. Best case is you get some engine compression braking to help with keeping everything under control. ”
A very interesting question, hopefully someone with real experience will chime in
With all the electronic systems in our vehicles, engine control modules, transmission modules , how much will actually work without and 12v power. Hopefully there is enough manual connection between the gear shift lever, the transmission and the rear wheels to assist in slowing down.
Ken