Metroplex's cog was damaged in 2005 during the Decepticon siege of Autobot City, which explains why he did not transform to robot mode during the battle. Perceptor built a replacement cog and entrusted its delivery from Cybertron to Autobot City on Earth to Blurr and Wheelie. This proves you can be brilliant but still stupid. Five Faces of Darkness, Part 1 After numerous setbacks, the cog was delivered just in time. As the city was under siege once again, Pipes quickly installed it, allowing Metroplex to fight off Trypticon. Five Faces of Darkness, Part 5