I would guess it has to be something to do with the neutral safety switch. Maybe it has a short somewhere? The very fact that by moving the shifter changes the pitch sound from the radio, indicates I would think that the switch is the culprit.
Also can you manually jump the starter? Will it crank?
and I'm supposing you have checked all the ground wires etc.
I have not checked any wiring. I am more inclined to think that the starter is jammed or I fried some wires. The car consistently cranked or tried to crank before, even with a drained battery.
I had my truck running with the jumper cables for potentially an hour next to the car, and was fiddling with the idle screws on the carbs, attempting to start, then fiddling more, repeat. I probably cranked more than 100 times in an hour.
I think it was either the night before that seemingly the same problem occurred once before. Cranked, cranked, then no crank. I walked away and came back and the problem disappeared. I was able to crank probably the 100 times mentioned above until:
- crank, wait a second
- oops, crank to early. Silence. As if it jammed or just died as the engine was settling backwards against the starter while it was attempting to move the engine forward.
Can the neutral safety switch get fried?
I still haven't looked at a wiring diagram.