Transmission leaking when a/c on and transaxle warning light flashes sometimes

I have a 2002 ford taurus that leaks transmission oil when I run the a/c. also the transaxle warning light came on when going highway speed, when you turn off the car and turn it back on the light is off. And when you stop at a light or stop sign the car acts as if its in neutral and takes a second to take off at normal speeds.