I doubt that tractor has DEF. It probably uses a DPF. A DPF isn’t my favorite thing but it seems to be fairly reliable. A lot more so than DEF.
DEF = diesel exhaust fluid. DPF = diesel particle filter.[/
You are probably correct
I’m running a Ram with DEF and from the reports, I’m lucky my DEF pump still works. They are a 1300 dollar unobtainiumm dealer part (800 aftermarket). So, that may be worth checking with the LS dealer