This seems to be a common thing with these tractors. It usually happens when you change the hydraulic oil or let it go low. You either have air in your system or the screen is plugged up. Sometimes you can just bleed the system and that will get your 3 point working again. Or you might have to clean your screen. There should be a bleeder plug on your hydraulic pump that you can bleed it from. You need to do this when your tractor is running. Crack it open until the air gets out. You need to move your lift arms up and down. If you have any questions, just reply or email me. Hope this helps. Bob
Oh, BTW, the little Super Dexta"s are very nice tractors. I had one for about 17 years.