2003 Mitsubishi Eclipse Transmission, code P0734

While driving on the highway at about 60mph my car went a into a "limp"
Mode, the neutral light was blinking and the check engine light came on. I would press the gas, but it would act like The car was in neutral. I coasted the car off the highway, the breaks and steering still functioned normally. On the side of the road I restarted the car, but it still acted the same. Fluid was leaking out of the bottom, it looked like transmission fluid. When I checked the transmission fluid with he dipstick it was still full. I had to have the car towed home where I pulled the codes and got a P0734. Could this problem
Just be a leaking line? Has anyone heard or had this problem before?