is your hydraulic tank over filled now?
as odd are it is , pending how much oil you put in it
but the same motor oil is supposed to be used in the hydraulic system on this machine
but WHO know;'s what is in in it
so, MY suggestion is, drain both motor oil and hydraulic system, use new filters and fill to correct levels on both using correct oil!
New Holland recommends this oil
10W30 2.5 GAL
www.newhollandrochester.com