Spur gears- G84307-01 is the stock number, diff. joint cups-GX12, 5x8x2.5 ball bearings, the cvd's are made of a pretty soft metal so you need extras and dogbone shafts, the stock servo's will go out pretty quick, all and all its a pretty durable truck if you take care of them.unlike me LOL. the thing that relly helps is to stiffen chassis. look at the cassis brace threads for help. I've got two a on road and offroad basher and there tuff little beasts.