I imagine a father or grandfather made this out of scrap lumber without a pattern or set of instructions. It measures 13 1/2" x 6 1/2" and is about 5" high. It is solid wood and weighs about 4 pounds. This toy truck dates from the early 1940's and comes from a farm in Pennsylvania.
Note that the front wheels are not round - they have been shaped by hand. It was surely made with love and what was materials were readily available, this hand-made toy truck must have made the boy very happy.