Transmission problem
2004 Dodge Neon 4 cyl Front Wheel Drive Automatic

2004 Dodge Neon 2.2L

My mom called me up saying the transmission is having problems. I checked the fluid level and it was out, I filled the fluid back up started the car and moved it around no problems at first. Then it all poured on the ground. I looked for a ruptured hose but found none. I then noticed that the fluid was draining out of the engine coolant overflow tube. I am puzzled because I am use to the transmission being a separate assembly on vehicles, but am not certain on this car. Is the transmission and engine connected more than I think internally, and do you have any ideas on what would be the issue?

Thanks,