How come no one asked the original poster what engine he had in his 9660? If I remember right, they came with the 8.1, then later the 9 liter. A neighbor did try a chip (canadian) in his 8330T. Fired off all sorts of codes, derated the engine, etc. Took it off, problems went away. The coding may change from year to year as they asked him what year his tractor was.