The Model 40 - John Deere Model 40S Standard Tractor Review
Model 40 Standards were the replacement for the M in the John Deere line of tractors. The serial number plate on these tractors state "40-S" . This was a one row tractor, popular with truck farmers and tobacco farmers. Small and compact, it was easy to maneuver in tight places. You could order special options on your 40S, like spin out rear rims.