M4n transmissions often leak - not sure why your raise eyebrows about a dry stick shift.

Pull the drain plug and look for metal bits or, better, pull the trans and inspect.

If it's dry and she drove it that, I'd wonder if the noise is the mainshaft bearing.

Is the body nice? 242s are pretty hot now. I sold a few I'd collected because they're impractical for hauling and I don't like working on pre-86 cars anymore. I wish I'd kept one in retrospect.
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240s: 2 drivers & parts cars