So got this 260z in great condition other then the hydro system. Speed in reverse and forward is good. Have not seen any air leaks or hydro leaking. Never felt the symptoms of air in the lines like one side not working in the morning or throughout the day, air bubbles in the resevoir. Always runs the same. The problem lies that when any stress is put on the hydros, like turning on a hill, turning fast, going up hill. Doing cleanups with the JRCO and Bagger unit I really notice it. During these situations the wheels/hydros squeal pretty bad and chutter like they were caught on something (like the wheels hitting the deck) but they arent, Ive checked the clearance. I did an oil and filter replacment and that didnt help. The mower has 450hrs on it. Any ideas whether its the pumps or motors? Ive searched but havent found the same issue.