My and my son were out yesterday giving our slash trucks some exercise when I started hearing a hard grindind noise coming from my truck. We were running them on a baseball field. That sandy dirt worked its way into everything. Thought for sure it was the motor being an open can. Started taking it apart to find sand behind the spur gear by the shaft bearing. Used a motor flush to clean the area, put it back together and was back in business. Does anyone have any ideas to help prevent this from happening again. Should have been a better design to enclose the gear cover by the drive shaft.