904 Transmission slipping/not engaging - new torque converter

Looks like I'm out of the woods. There was a combination of three things messing with the car and with me:
1) Smaller engine (170, not 225) = feels less powerful... duh
2) Brakes were hanging up
3) Needed some transmission fluid - I didn't put enough in the torque converter
Car is driving and shifting. Even the kickdown is working properly.
Thanks for the help!