We have this CIH DX55 tractor at my work. Out the blue, the lift arms on the 3-Point hitch do not work, and they are stuck in the raised position. They operated fine a month or so ago when we last had the 3-Point mounted mower on the tractor. I was recently using a front end loader on the tractor, and the loader worked fine. Dropped the loader this morning and wanted to go back to using the 3-Point hitch on the rear. Backed the tractor up to the mower, and the lift arms won’t lower. So wondering what’s going on. Hydraulic oil is full. I tried cycling all the hydraulic control levers on the tractor, including the draft control, rear remotes, and the loader joystick. No go. I had my co-worker stand on the lift arms hoping his weight would break them loose. No go. So I’m wondering if anyone else has experienced this with this model line, and if so, what did you have to do about it to get it working again. Thanks for any help or advice. Rick G.