I had the same thing with a 1/10 buggy, WOT but mine stuck on full lock too, hit a wall lucky there wasn't too much damage, only went ten feet. At first I thought it was the receiver so I swapped that out, all seemed to work so ran it again, guess what, did it again, no damage this time. I swapped transmitters this sorted it, odd thing is it only did this with the engine running, all worked fine on the bench, can you try another transmitter?