2002 Audi S4 triptronic
 

Goes reverse, but will not move forward. All gears selected on display. Before this happened, It would have problems accelerating. Act like it slips into neutral just about every time as it is time to up-shift. I was hoping it was low on transmission fluid. I checked the fluid and a little over a quart flooded out (black and thick) could this be the torque converter? (I will be changing filter and fluid no matter what) or could the sensor plate, or whatever it is called, for the gear shift be broken to cause this?