I don't know if you're being sarcastic or not, but this is a terrible idea. A family is driving on the highway. Kids are fighting in the back seat. The mother, who is driving, turns her head and tells them to stop. The car is rear-ended by a dump truck, and all three are dead.
I have to assume modern auto transmissions have computer lockouts to prevent you from money-shifting it into R while at speed, don't they? I'm thinking like modern dial-a-shift where you aren't directly manipulating the transmission with the shifter.
I've never tried to test it cause I don't like horribly expensive mechanical noises, but yeah.