Changed alternator, now car goes into drive but only revs, then battery died.

Changed alternator, now car goes into drive but only revs, then battery died.
The plug on the alternator (pigtail?) was broken during removal but wires
were put back in. 30 mins into the test drive, the car would no longer
accelerate but only rev up as if in neutral. Stopped the car, turned it off, and
looked under the hood. One of the wires were out and so I put it back in.
Then the car died. (It died because when the alternator originally went out,
my wife was alone, in town, and the belt broke off. She continued shopping
and driving, so the batter y is drained I'm sure.) My reason for posting this is
that I hope that it's not the transmission. I cannot check the fluid because the
car won't start and we're waiting on a new plug for the alt (pigtail?).