Hitachi EX120-2 Swing motor seal

I have a Hitachi EX120-2 serial #72N-30953. The swing motor is leaking all the gear oil into the belly. I am wondering if anyone had a source or a part # for the lower seal. I do not have a parts manual and my Deere dealer isn't being very helpful. It is the same as a 490E.

Also, does anyone have any experience/luck just putting a seal in without going through the whole swing motor? We only put 100-150 hours at the most on it screening soil at our yard. It shows 5800 hours on the meter but...

Hitachi EX120-2 Swing motor seal

Hitachi EX120-2 Swing motor seal