Recently bought a 2004 JD5205 2WD and had it delivered. I’ve driven it a couple times and hydraulics on FEL and steering wheel was smooth. A couple days after getting it the hydraulics began to chatter significantly when lifting the FEL and box blade up and the steering wheel is now jerky. Lowering the attachments act smoothly. Curling the FEL upward is very, very slow. I’m new to owning a tractor and it appears that the hydraulic oil is visible in the sight glass. Tractor has 617 hours. Any suggestions as to possible issues while I keep researching?