Will drive fine in reverse, but in drive, it feels like its in neutral.

Hello,
I had a student driver drive my van and this is what happened. He thought it would be cool to rev the engine really high. As he did that, he shifted the automatic from park, into drive. Once it hit drive, a little snap was heard and the trouble began. Now the car can drive perfectly fine in reverse, but once you put it in drive, it feels as if it was in neutral. You can rev it up when its in drive, but it won't move. I've been searching for a way to fix the problem, but I got no answers. Somebody please help me figure out whats wrong, and the estimated cost of repairs. If its an easy fix, I would love some instructions. Thank you for your time.
-Sam Figura