Some states have ag equipment lemon laws but they typically apply only to tractors and equipment used in an ongoing agricultural operation. They are very clear about what the responsibilities of the consumer are. A tractor that has been used for 3 years for personal or non-agricultural commercial use would not likely qualify as a lemon under the laws of my state. No offense intended here, but in this case, the owner should have forced the tractor back on the manufacturer much earlier in its troubled life. JD may still try to help rectify the situation, but they are most certainly not obligated to do so--based on what I read above. At this point in the life of the machine, I doubt any tractor company would do anything more than offer to fix the machine for the cost of labor--at best. Even that is a stretch. Here is a link to the Virginia Law, which is similar to Delaware's law (but on-line):
Ag Equipment Lemon Law of Virginia I couldn't tell you if Missouri has any such law.
Bottom line: if you smell a lemon or a chronic problem in the first couple of months, force the tractor back on the manufacturer. If you figure it out in the first year, or so, you can likely work something out to trade for a new machine at a depriciation cost for your hours of useage. Beyond that, ANY tractor company (or car company) will just keep fixing the problems under waranty until that time period is done, unless a lemon law can be called upon. Beyond the warranty period, you are on your own.
Good luck, though. It sounds like there is plenty of documentation to make a case with JD for a long, troubled history. JD corporate is the only hope now. The dealer cannot be expected to pay for anything out of pocket. It just ai'nt reasonable. If the dealer does anything free at this point, he should be commended and rewarded with customer loyalty. My delaer went the extra mile and he has mine. I know somebody is going to take issue with this point about the dealer not digging into his company's pocket, but the realities of running a "franchise" business for profit rule this issue.
JD corporate will listen, but you might have to be persistent. They did in my case. If the company (JD, Kubota, New Holland, or any other) feels the problem is repairable, they will do only that. In my case, they took my leaky 2210 trade-in at a minor depreciation rate and cut me a great deal on an upgrade to a 4110. I truly believe that is as good as it will get in most of these cases when time and machine hours have accumulated for more than a few months.
Finally, all the talk in the world is just talk. Put your issue in writing and you will get a better response from any company, JD or otherwise.
Good luck