HELP! Stuck in a gear
 

I have a 2000 Galant, V6. It seems like my transmission is stuck in a gear. While driving at around 50 – 65 mph, the car jerks really hard and then runs at a higher RPM (about 3000 rpm). Only when I pull over and turn off my car and re-start it that the problem goes away and it drives normal again, for a while, then it happens again. Then I’ll pull over and turn off my car and then restart it again. I had to pull over to restart my car 4x on the way home.

Could the problem be the Transmission Electronic Control Module? If so, where is it located?

Thanks