Happened to me a few times. It's almost always because the antenna wasn't on while the upper hull was off, the transmitters was too close to the tank and or the antenna wasn't deployed fully. Put the whole tank back together the way it should be, keep a proper distance away from tank and deploy your antenna, it should work fine. One time it was the transmitter itself causing me to think 2 tanks had gone bad at the same time, kept swapping crystals and two different tanks were acting up until I changed the transmitter and voila! Problem solved.


Now, as for your gears, you have to take the gearbox apart and file the gears individually to get them to mesh properly. Testing and filing 1 pair of gears at a time. I used a dremel tool.