The GM part numbers for the shaft and the one longer bolt needed, have already been posted in this thread. This thread is so overgrown with bad info and duplicate posts as to be cumbersome and non-helpful.
Last I heard, the GM shaft has been discontinued, but there were still some in dealer stock unsold. Another guy claimed they weren't discontinued, just "supply chain problems".
Anyway, I bought a new GM shaft about two years ago, and the Stealership also had the "special" bolt. Dorman supplied an aftermarket version. I don't remember the Dorman part number.
Shaft (From C3500HD, I think.)
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Longer bolt for U-joint shaft, above, compared to orignal bolt used with rag-joint shaft.
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