I have a traxxas bandit with a VXLsystem and a 2s 8000mah SMC lipo.

Iwent to cinci about 2 weeks ago because my sister had a soccer tournament, and my parents forced me to go, so to give myself something to do, Ibrought my bandit and my brother brought his rustler. We found a construction site near the field they were playing on, and it had HUGEmounds of dirt and rubble. We played around on those for alittle while, until my bandit just stopped. Well, it turns out that the little pin that turns the rear wheels had fallen out somehow. No big deal, we went to a hobby shop around the hotel and got it running again. Then, at home, about 3 days later, the same thing happened on the same side (left). Ireplaced it and kept bashing. Then, yesterday, it happened again. Iwas starting to get annoyed. Ihad never had that happen before. Then tonight, about 20 minutes ago, it happened AGAIN! Am Idoing something wrong? Does something need replacing? I also have a traxxas slash with a VXLand the same lipo, and that has NEVERhappened in the 9 months Ihave owned it.