Do Shift Knob Compression Sleeves Go Bad???...
 

...or is it just because of cold weather (50 degrees here in LA is considered cold to us!) that my knob keeps flying off on me! Just curious.

I had to cut my shift knob off the thing was on so damn tight. Little colder here in Chi Town.

My factory shift knob just unscrewed. I figured the threaded rod was part of it. Found out later it's a bolt ... but still, the knob just screws back on. I have not had to take the cap off t get at the bolt head. I've since turned a shift knob from cherry, tapped it for an 8mm thread 1" deep, and screwed a 2" piece of 8mm threaded rod into it. It also just screws on and off the lever. The hand-built eccentricity keeps it tight enough so it doesn't move on its own.

You might want to look very closely at the knob itself to see if the neck in which the sleeve fits has started to crack. The same thing happened in my 75 but the neck was obviously split. It's possible yours is weakened, allowing the sleeve to lose its grip on the lever.