Well after about 2 years of doing every thing I could think of,every thing people told me ,don't know how much kubota hydraulic fluid and filters I've bought ,changed out the pump to no effect ,my son told me run it without the Fil cap in,bushhoged for two hours ,not the first drop of oil came out,tapped the filcap put 1/4 " line in it bushhoged 2 hours today still no oil came out ,so I guess there is a vent line stopped up,sure has cause me a lot of trouble