Typo???
Do you mean L3240?
They didn't make model L3420.
If you do, I hope you get it for one seriously good price.
Like in the range of 5k!
With hours like that I doesn't matter if they spit polished it every day, its about completely worn out, and your looking at some serious expense to fix it as things give up.
Don't get me wrong I think Kubota's are great, but 4000 hours is a lot of hours of wear on any piece of equipment.
In comparison it's like buying a truck with 300,000 miles and expecting it to keep going.