Belarus 530 clutch

[Dove777]

Can't get the clutch to disengage. Was working 2 months ago in low gear (not in high). Push it down, and it just grinds away. Found a 1" plug on side of clutch case. it was empty. Put some fluid in it and found 4 holes on bottom of cassing. Look like thay are factory made.
Are the holes suppose to be there?
Should I adjust the rod ( can make it shorter)?
What am I missing (beside my mind)?