I was wondering if a question like this one would be appropriate for this stackexchange or if it belongs to another one (or none at all at the moment, from my browsing, this one is the most appropriate, but it's still not completely on subject :/).
I'd like to know what would happen if a car was placed facing downhill a long straight road, with the automatic transmission engaged in first gear, with the brakes getting released (the car would start to go forward, accelerating, that I know). Mainly: would the RPMs needle come up, if so, at which rate? Would the torque converter lockup, if so, when and what would be the effect on the whole car (would it suddenly slow down)? Would it upshift at some point?