I just recently purchased a used 3XL maisto rock crawler, without a remote. So yesterday, I decided to installed a 1/10 speed control , and removed the stock circuit board. I ran the negative/positive cord to both front/rear motor. I also installed/upgraded servo. But as I plug a 9.6 v battery, I turned on remote n press forward, it went forward. I then put to reverse but won't run to reverse,so now I'm stuck with no reverse. So anyone know the problem? Everything works but no reverse. Any help would be appreciated.