I agree with the bad rings, but usually a 4 cycle diesel wonb't run
away with blowing oil due to bad rings. now a 2 cycle (jimmy?)? thats
a different story,and yes, they will run away! But on your tractor,
you'll probably find hints of diesel fuel in your crank case as well.
Not always, but you might find that it's being traded out. Does the
engine have a lot of blow by as well?