My '69 console auto shifter has a circlip on the bottom of the knob to keep it from going down, and another circlip under the bird button to keep it from pulling up. It is also indexed with a pin to keep it from spinning. Once the shifter knob is securely in place, the bird button should snap in properly. I just had it apart over the weekend for cleaning and lubrication, and it works like new now.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching