John Deere 317 and 318 are very similar and have almost the same functions. New models were introduced, including the 318 which had an 18-horsepower Onan engine, and the 317 was retired from production. With almost identical tractors, the 318 and the 317 differ mostly in power steering on the 318, but not on the 317. With the 317, you have a PTO and dual hydraulics on the front, but with the 318, you have a hydraulic at the rear.