I rechecked the casting number and the parts book gives a range (I only looked at the last number). The range is 3702244 thru 3711483...sorry I missed that on the first go-around.
Three different parts books on my desk...
I think you need that gear, unless you break out the big welder and fix it forever with no hope for repair.
If you're OK with HI only, look for a single speed 6.17:1 and swap pumpkins...very easy.
I've always known this rear as the "1955-59 15,000 pound Corporate (GM) rear". The other axles used at that time were made by Eaton.
Hope this helps,
Mike B
