Here is Charles Hider’s design for steering a chain-drive axle. The axle pivots in a U-joint-like device with the spur gear differential seen on the left. The chains and sprockets always stay aligned. The tubes you can see in both sides of the shot lead up to the steering gear and that’s how the entire axle platform is pivoted—pretty clever solution to steering a chain-drive truck, though not practical in 20/20 hindsight. Both axles are identical.