I think it is the one way bearing. I ran Traxxas 20% fuel in my monsoon and my other truggy when I bought them and had the bearing problem. I read that when you clean it with contact cleaner, they dry it out and put a dab of motor oil on it then reinstall it. Do make sure you install it correctly because it will go on both ways. If it goes on the wrong way you will think you did not fix anything and it will not turn the motor over. As far as getting the rest of the oil out of your motor you should not have to do anything but run the new fuel you choose to buy. All I did when I cleaned my bearing was flip my truck over and drain the tank, refuel with new different fuel and start it right up and run a tank through. After that I have never had a problem again. Nothing wrong with the traxxas fuel but if you are going to you nothing else but the rotostart you do not want to use that fuel. If you only wanted to use a bump box then the traxxas fuel would be ok.