Inside the stick is a bonded rubber bush. If the shaft is as loose as you say it should pull off. Having said that, the short ball ended part that works the gearbox has a flattened end that is bigger than the section below it. It sounds as if the flattened part has torn away the rubber so is able to rotate. When pulling it out you will have to get the flat end to pass through the smaller hole in the bush. This may require some effort. Awkward but some silicone spray up there could help. Best to obtain another complete lever in good non rotating condition before tackling the job so you can just swap it in. You can then tackle this one on the bench in your own time.