My dad thinks its either Clutch or Brake problem...
We're taking it to the hobby shop sometime this week.
I hope its not a $100 problem!
dont take it to a hobby shop! fix that sucka yourself, thats the way you learn about your car. but yeah check the center cvd and make sure the set screw is there and if it is tighten it up, most of the time there is a flat spot or rounded spot for a set screw on the diff shaft may want to even loctite it.