I have an 85 M4050 and the lift arms are stuck in the lowest position after being parked with lift all the way down. draft control does not appear to be engaged. Changed fluid and cleaned filter a few weeks back, all looked good. Fired right up and lift worked as it always has. Did some bush hogging and parked for a few weeks. Fired it up yesterday and the lift arms will not raise. I still have the bush hog attached, if I back uphill with position lever up the arms are forced up by the bush hog and stay up as high as the bush hog pushes them. Arms will lower if I lower the position lever but will not raise. Any trouble shooting options or idea why it would suddenly lose lift? Maybe linkage issue or stuck valve? My wallet hopes it is not a pump issue. It has never had any hydraulic issues in the past. Thanks in advance!