That looks different to the one I was referring to. I have a mazda box. On that, the stick is plain with a plastic sleeve, over which slides an aluminium threaded cylinder, held by the grubscrews. The knob then screws down onto the threaded sleeve and the ring screws upwards to meet the knob and secure it in position. There is no lift detent.
Looking at your pics, it looks like your stick is actually threaded. I am also a bit confused that the knob is circular whereas the lower section on the stick is a “flattened” circle…so wondering how they come together.
Looking at the knob, I can just see the grub screw entries. Looks like you need to unscrew that cylindrical piece (with the rough cut on it) from the actual knob itself. Is there room to get a long nose locking pliers to grip it? Once it’s moving, it will probably come out easily.
You would then screw that bit onto the gear stick and secure in position with the grubscrews and finally screw on the knob part. If you have a gearchange motif on the knob, it might be trial and error to get that looking the right way before finally securing.
