Before you buy a new halfshaft, you might try what I did when I did the same thing which was to buy a die nut, cut it in two and then put in on the lower section of the shaft where the thread was good and wind it back off cutting a new thread as it went. It worked perfectly and a cheap die nut was around £10 on e-bay and the die wrench was about the same.

 

Yes that would be a better Idea, I did suggest re-threading it.
What would we search for just nut and tool?

 

Sorry what I mean is, the nut was imperial and I'm not sure what to type in on ebay search engine

 

I think mine was a 7/8 14 UNF die like this https://www.ebay.co.uk/itm/UNF-DIES-...o5y9KK4a1sRBqQ

Possibly cheaper from a chinese supplier but probably not a good idea to order direct at the moment....