78 K20 auto can't shut off truck in neutral

[78 k20 8,400 gvrw]

So I've been lurking around your forums for a while now and found a lot of good advice on here so I'm hoping to get some more. I tried searching this and found nothing. I can't get my truck to shut off in neutral.
I'm fairly familiar with the Chevy steering column and have the lock plate tool to disassemble the column, but I'm not sure what I need to do to get rid of the park lockout that's preventing me from shutting it off in neutral.