The diff is some weird nylon or plastic of some sort.. most of the parts are cheap and its been in production so long... u can upgrade as much as u wanna spend. I've been replacing broken parts with titanium and carbon fiber for cheap as the plastic and steel.. depends on if its a rtr or t4 kit or what ur into.. I can't find any reason that I would get something different unless I went bigger
But no it has.. (mine has 2 aluminum pinion gears) 2 plastic spur gears.. I guess its plastic. Plastic's are pretty tough these days... I guess I thought I saw diff gear instead of pinion but I have no more trouble with either other than normal wear... or the one pole in the parking lot that seems to have a magnetic pull on my car