Back up light switch vs. column shifter

On my 66 dart, 904. The column shifter is a little too loose and is affecting the back up lamp switch. I have to giggle the column shifter up towards P in order for the switch to flick on the lights. This is due to the amount of freeplay between the shifter and the tranny linkages.
What is the process of firming up the linkages?
I have tried adjusting the back up switch but it is maxed out.
Help?
There seems to be a very tiny window of opportunity for the switch to kick on the lights.