Where is serial number on a JD 4020?

The serial number on a JOHN DEERe 4020 tractor is typically located on the left side of the engine block, just above the starter. It can also be found on the right side of the tractor, near the rear axle on the frame. For some models, it may be stamped on a metal plate attached to the tractor. Checking the operator's manual can also provide specific details on locating the serial number for your model.