My crystal ball that I consult for model and year identification of what you are working on has gotten quite cloudy today after the spring rain storms.
So a general reply would be in order.
If it is something older like most fellows here have, I would suggest a fluid and filter change if it is a 30-40 year old machine.
Now if it is something much newer I have no clue.
On a side note, the older stuff that had the sunstrand hydro's are pretty much bullet proof and you shouldn't need to have someone go inside it.
As most parts are very expensive, and don't generally go bad unless someone drug it down the road with a motor vehicle.