A pin box includes a frame, a swing arm pivotally connected to the frame, and a pivot plate pivotally connected to the swing arm. An air spring disposed between the frame and swing arm may be selectively compressed and decompressed. A dampener connected between the swing arm and the frame dampens movement of the swing arm with respect to the frame. A rubber spring disposed between the pivot plate and the swing arm is selectively compressible there between when the pivot plate pivots with respect to the swing arm.