I had not thought about the possibility of it being an "off ground" safety shutoff. I think you are correct about that.
I have been through the whole valve body and cannot find anything that is wrong. It will power up and run like its is supposed to but when you let off the hydraulics is makes a terrible noise from the gear housing. Obviously it is not bypassing properly. i do not see any simple check valve in this housing. To be honest im not sure why this housing is anything more than a check ball besides what hvy 1ton said about it being a off ground safety.
Bobcat has their parts diagrams available online at [url]http://bobcatpartsonline.com/bobcat/[/URL]
You must use Internet Explorer and your pop-up blocker must be disabled, or you will not be able to view the diagrams.
In the Model dropdown list, select Rotary Cutter. The next screen will allow you to select a specific model. I saw diagrams that showed a lever attached to the valve.