I have a Gehl 3610 early 90"s. Had it for years with no problems. Today I was clearing snow from my property, and after maybe a half dozen moves the lift arms will not lower. They raise as they have always, and the tilt arms function fine up and down. It is T-handle control. When I push the bar to lower the lift I can hear the pump engage, but no response. From that I would assume that the solenoid and pump are functioning so I really don't know where to start with it. Any advice or direction on this would be greatly appreciated. THANK YOU.