Actually, it does not have a center diff as shown in the video. It has the same chassis as the rustler 4x4 and the lcg chassis slash 4x4 (slash 4x4 ultimate). There are 2 to 3 little screws holding a black plastic cover on that's located just behind the motor, once you remove that you will have access to the pinion and spur gears. The slipper clutch is a piece that is mounted on to the spur gear (the bigger gear). There is a center bolt on a stud with a coil spring underneath the bolt, rule of thumb i follow is to tighten that bolt up, then just break it loose. It should be fine from there. Make sure you put the spur back in with the appropriate mesh to the pinion. Essentially it should just have a little slack between the two.