It's not the torque converter. Its more than likely the bands in the tranny. So, you'll probably notice an improvement flushing it and changing the oil/filter. It's going to do it again though. Basically once it stops it doesnt quit happening.

To put it in, you're probably best off to just pull the motor and split the trans off after its out and on the ground.Its a royal pain to do a transmission while it and the motor are still in the car, in a FWD.

Your probably best off looking for another trans.