Well, while running my Slash 4x4 today it started making a grinding sound in the rear gear area after just a couple minutes of running it. After taking it apart I found that the rear diff bearing was busted and little ball bearings were all in my rear housing.I've only had my truck for about 3 weeks so I was pretty shocked to have this happen already. Has anyone experienced this problem and is the only thing I have to replace going to be the bearing? Part # 5120