I'm thinking that all you did was break the wire for the O/D button. Right? This is normal anytime you want to remove the shifter.
To properly return operation to the o/d button, simply remove the shifter knob again and take a look at the wires that were broke. Now, take some wire of the same gauge (you should be able to just look at the size and see about what size is needed and you will probably find that you have some lying around somewhere or in something in the house) and just elongate the broken wires located in the shaft. Make them long enough so that you can reattach them to the wires that connect to the button in the shift knob while the shift knob is off. Then just stuff the extra wire into the shaft and reattach the shift knob, securing it with screw.
