Sounds like the problem is just in the ignition switch. That is a cheap part which attaches to the fwd side of the stalk w/ 3 screws (flat screwdriver). The problem is not much room to get a tool in there. Perhaps try a dollar store mini-ratchet tool.

In my 1984 300D, rotating the key would hang on something. It wasn't in the tumbler. I removed the flat steel plate from the stalk and found the spring detent had broken off and was jamming parts. I removed that. Don't have the detent, but the key has never rotated while driving (aka infamous GM switch problem). Wish I had left the steering lock out when I re-assembled since don't need that anti-theft.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans