You'll have to pull the old one straight off the shaft. Try twisting it as you pull, they are usually stuck on there pretty good.
it sounds like your neutral safety switch
The dash cluster needs repair. This is not a DIY job. Take it to a dealership.
Should be a removable panel under steering column. where adjusting screw is located Place gear shift in neutral to adjust
Is this a standard transmission, or an automatic? automatic
This question has already been answered.
Check
VERY CAREFULLY.
Remove the linkage off of the trans and shift it there.
Automatic or manual.. That's a broad question
I doubt very much that the knob will come off of the automatic column shifter.
Remove the engine and drive shaft
1. Remove the knob from the shift lever (it is threaded onto the shift lever). 2. Remove the shift indicator assembly from the console (it is held in place by either 1 screw or 1 rivet located at the rear of the shifter slot). 3. The console is attached to the shifter assembly by two screws and also attached to the floor by screws located inside the storage compartment. If you need more info, I have a dealer's 1965 Buick chassis and body parts book (printed in May of 1965) that has many parts break down figures with all of the GM part numbers.