I’ve push started an automatic with a weak battery. You can’t do it with a totally dead battery. The automatic transmission won’t push hard enough on the transmission to turn it over, but it does help. You need to do both, roll in gear AND use starter. Together the two will start up your engine. Sometimes. I’ve done it before. It’s really not worth the risk(imo) because if it doesn’t work, your car is stranded. I’d rather leave it in it’s parking spot and jump start it.
The other thing is, you need to get moving pretty fast...like down a long hill.
Also, you need to disable the neutral start switch. Doing so on a modern car is probably impossible. actually, push starting anything with fuel injection is impossible as well, unless you have enough battery power to pressurize the fuel lines. And now that I’m thinking more about it, there is a lock on the gear selector lever on modern cars that won’t let you shift out of park without depressing the brake. If there’s no battery power at all, you may not be able to get it out of park.
I suppose it is theoretically possible to push start an automatic with a totally dead battery if you got moving fast enough...but I’ve never tried it and I’ve never heard of people doing it.
ON the other hand, I can “jump-start” my Prius with a 12-volt hand drill battery, and a couple of 24-gauge alligator clips.
You would also have to have an automatic that has a rear pump. You cannot do this with any car built in the last 20 years.
There is frequently a release button. I've got one car with about a quarter inch by quarter inch little cover labeled 'shiftlock release' on the console near the shifter - I've never popped it open to see what I'd need to shove down in there to actually trigger it. Another car,you pried off the console cover, reached in beside the automatic shifter, and flipped a small, unmarked button that was normally fired electrically.