tractor labour ploughing, serial number 7U1941 I used to sit on the oil can too when I was a little boy. Later I operated long hours with no pay because I loved it and grandpa did too. reat video mate. Iv got a D4 30 A . They were much like the 7 U model but before the D 4 C model. It was made in Mexico in 1954 and less than a hundred were bought to Australia. Surprising how many little changes were made during a production run of a series.