You might want to change the fuel filter just to rule it out. If you dont have a tach, listen carefully to the sound of the engine. Is it speeding up while the tranny slips, or is the engine hesitating and then lurching forward?? If you can't get a reading on it, try taking it to a trans shop and a dealer to get a couple of opinions. You wouldn't want to buy a transmission for a car that needs a fuel filter or spark plug wire. If you know a good mechanic, give him/her a visit.
