I was using my ECX amp, perfectly fine for 30 minutes in my backyard, no issues... but the next day, I walked all the way to a school parking lot to use my amp, and the pinion gear completely fell off. I screwed the pinion back on, tightly, but the pinion kept on falling off as soon as I hit the throttle. Can someone please explain WHY? And HOW? I didn’t change anything in my gears, it just randomly fell off, even though I used it perfectly the day before!