You'll need to change "Gear ratio" and "Pulses per revolution" in your bin file. I had similar problesm last year i went from 2.93's to 3.29's. The tranny didn't know where the torque converter was and it (tc) wouldn't lockup. The tranny constantly overheated because the torque converter wouldn't lockup. Also the shifts were really hard, now matter what i changed to soften them up. Once i put in the correct values all the symptoms went away.