Kubota's are pretty reliable - mine was back to the dealer once 19-20 years ago at the 50 hour service and to repair a leaking FEL cylinder. Since that time I have done a few repairs, normal filters and oil, another cylinder re-seal and welded the BH bucket flange, replaced battery and fan belt.
I buy parts/filters when needed from Messicks - but you don't have that option in NS - and dealers are not as common as here in US. Also that is a part that is not commonly used so limited stock I would imagine, or users weld them until they get around to replacing the hub,
It seems your JD dealer is about the same response wise for a potential sale which is not a good sign, so maybe stick with orange!