We had a JD 4020 on our farm when I was a kid. I think it was made in 1969. First new tractor my dad ever bought. He loved that tractor until it started giving him fits. Worked perfect for a few years until it didn’t. Transmission, hydraulic pump, electrical system. They all started going bad. I was in high school and can remember getting off the bus to see a guy winching it onto a trailer. My dad had the biggest grin but wouldn’t tell me where it was going or what kind of deal he made to get it off the farm. Always knew he came out on the upside of the ledger when he got rid of that tractor. Hope you have a great run with your 4020. Cheers! Whipple