Page 9 outlaw owners manual:
On all Bad Boy commercial models, the hydraulic oil and filters need to be initially changed when mower has reached 50 hours of usage. Each subsequent changing of the hydraulic oil and filters needs to occur 500 hours or once a year. The required hydraulic oil is 20w50 motor oil.
This is taken from my 2010 outlaw owners manual. Most tractors like farmers use also recommend a 50 hour hydraulic service, gear box service, and oil change on a new tractor.
If at first you don't succeed, try and try again.