I can't say I have a solution for you but a bit of sympathy, this has happened to me too. I had a few more hours on mine but it happened one day. I could do the steering but forward and reverse didn't work. I kept working on it and had it to where it finally had forward to work. After a while it started cogging bad and finally back to steering no R and F.
What did I do? I called Traxxas and they said to send it to them for service.