I would need to refer to a factory service manual to be of more help. Having been at it so many years and into some many columns of every model... They're all the same but different to me.
In another's thread I stated there was a set screw accessible through a hole in the column bell. Someone else discounted that statement leaving me to think the set screw I recall must be in a GM/Ford/other, column.
We might assume there is a spline/rib like a square key that locates the tube OD to the casting ID and you simply need to tap downward on the shifter lever at lower end to persuade separation. We can be sure there is something of this nature attaching the 2 parts.
The service manual ( free download ) is always the best route. Good luck with it.