In Reply to: Ford NAA posted by Larry on November 16, 2018 at 02:04:30:
Oil viscosity depends on what the temperature is where you live. Most run that Rotella 10-40 in there tractors. I bought synthetic 5-40 for my Ford 3000. I use it to clean snow in the drive and it get pretty cold in Northern Indiana in winter. Any good oil will work and is much better than what the old tractors originally used. I think if I live in a warm climate I'd use straight 30 weight. Just my 10 cents worth.