My Branson 3510ii has had a hiccup (bounce) in the 3 point hitch for quite some time, but today it became a major issue. I seem to have lost some of my hydraulic power, and if I have the hitch under load and use the loader, the hitch drops slowly. As soon as I stop using the loader, the hitch returns to the up position. I also have a new noise coming from the rear of the tractor - a hissing sound that sounds like fluid leaking through a valve. I figure I’ll have to rebuild the rock shaft piston, but suspect there could be more going on. Any help will be much appreciated!