Drive shaft is stuck

I cannot get the tiller tine drive shaft loose. All the videos I've found show pristine Mantises, and the shaft is easily undone. I'm working on its left-hand side (as I face it with the handlebars in my hands), and use the appropriate 'leftie-loosie' thing (AKA: Counter-clockwise) as shone in all of the videos. But the darn thing just will not unwind. Any help?