I just took the car out to drive, and the condition is the same. However, if it starts to pull, then I come to a stop, the transmission will not pull again until I put the car in park, then back into drive and wait again.

I checked the fliud and it shows proper level on the dipstick.

Does this sound like the tranny is fubar? It's a used one that was put in 2 years ago, out of necessity.