I just bought a 1800a gas and love it, and now I have the oliver bug and want another one with more power. I saw an 1850 diesel with just the two speed in Lori Lin Farms in Orrstown PA for $5800 and I am thinking on going to look at it. I like this model because the two speed seems much easier to work on that the ones with hydra power. Is this 1850 model a good overall tractor and was the diesel motor reliable? What are some obvious problems I should look for when testing it out? I don't have experience with diesels other than my JD 720. Do you think $4000 a reasonable offer for this tractor? If you search on tractorhouse you can see the photos.