chris : I have replaced the rear crankshaft lip seal and have helped 2 other C34 owner replace the front crankshaft lip seal. You have to remove the engine to replace the rear, but the front can be replaced with the engine in place.
Truthfully I do not recall (but think I did) if I wrote an article on replacing the rear seal.
I'd recommend that you contact your local Kubota dealer.
The front seal was easy, but the rear was more difficult - especially if you also replace the race that the seal rides on.
A few thoughts Hope this helps