The Allis Chalmers FD4 is a simple and reliable tractor built for basic farming tasks. It has a 4x2 chassis, which means it has four wheels but only two of them are driven. This type of setup is common for smaller tractors used in lighter work.
The FD4 is a two-wheel drive (2WD) tractor. This means the power from the engine goes to just two wheels, usually the back ones. While it might not be as good in tough, muddy conditions as a four-wheel drive tractor, it's still great for many farm jobs. Allis Chalmers was known for making sturdy, no-frills tractors that farmers could count on, and the FD4 fits right into that tradition.