I am trying to picture what you have done.
You have elongated the slot allowing movement of the shift box up the column beyond what was designed.
The purpose of the original slot was to allow movement of the shift box to adjust the distance between the end of the shifter handle knob and the steering wheel to avoid it from interfering with either the steering wheel or the dash.
I am assuming that the "collar with threads" is at the top end of the shift box shaft where it meets the shift arm.
If this is the case, I would be concerned about whether there are enough threads engaged in this area so as not to wear out and let go over time.
These threads were not designed for adjustment of the above mentioned shifter knob positioning. The slot in the mast at the shift box is where the major adjusting takes place.
I would not be worried about it except that the threaded collar is not made of the most durable of materials and many of them wear out from normal use.
Now if your "adjustment" of the collar resulted in engaging more of the threads and not less of the threads, then you will be OK.
Carl
