Thanks for the comments guys. I greived for a few hours until my local Mahindra dealer brought me a used 5075 to use until I can decide on what I want to replace the dead one with, which may be a 2021 6065 Cab model he has with 120 hours on it. A significant upgrade, to say the least... although a LOT more expensive than 18 years ago (to be expected of course).
We just recently had about 230 tons of crushed stone (I call it slag) laid down on our dirt road (about a mile long). I was smoothing it out with my Duragrader as I've done for the last 18 years, and after about 30 minutes or so, I started smelling burning. There was a lot of gray dust from the rock (extremely dry) so I didn't realize it was from the tractor. I just thought someone was burning a field or trash somewhere. I kept looking around for where it was coming from, but couldn't find it. Then I realized it was coming from the tractor as it got a lot thicker and smelt odd. I thought it was overheating smoke, but then I saw fire flashing out from under the fuel tank. My thoughts were that I didn't think diesel would explode, but then again, I wasn't going to hang around to find out. I didn't have my phone and was about 3/4 mile from the house. Nothing at all around to put it out with, so I started walking back to the house (a neighbor that lives closer was at a funeral)... about the time I got where I had to turn and couldn't see the tractor any longer, I looked back, and all I could see was black smoke. I knew it was a goner, and there would be nothing anyone could do. Even if I'd had my cell phone with me... by the time the volunteer fire department got there, it would be too late. It was too late, even within a couple of minutes of me getting off the tractor.
The volunteer fire department did come and put out what was still burning, and then I had it towed back to the house.
Not sure what caused it, but we all figure it must have started leaking somewhere under the fuel tank and ignited in some fashion in that area. It may be difficult ever to know the exact cause.
I pulled our Quickbooks accounting ledger, as I couldn't remember if we were still paying for insurance on it. I see where we paid State Farm $151 back last July for tractor insurance. I think I have $15,000 property coverage on it. I'll be calling them first thing Monday to find out. That will help some with the replacement.