I don't know about the temper, but I've also heard the rebuilds aren't that
great, because they supposedly machine out the inner and outer hubs and put
in bigger balls.

However, that said, my LF shaft is a rebuilt one (PO) and I recently
serviced all the CVs on the van.  While I had the LF apart, I miked the
balls in the rebuilt shaft.  Comparing them to the original parts, I
couldn't discern a difference--my mike isn't super accurate, but provides a
good SWAG.  Perhaps they replaced the inner hub only or something, not sure.
I have a feeling that "rebuilt" means different things to different people.

Given that CVs only cost in the $55 range, and a rebuilt shaft is $99, I'd
just use new Loebro joints if it were me.

Also, I'd try to get a puller to remove the old joints if I were you.  The
hammer/punch method works, but the puller is a lot simpler in my opinion.
Whatever you do (puller or hammer), make sure you only put pressure on the
inner ball hub, never the outer.  If you use the outer, you'll crack the
ball cage (not that I've done that or anything) and then you get to buy a
new joint for sure.....

tx,
bmc  :)

"Faith will move mountains, but you'd better bring a shovel...."

  Have heard that the rebuilt halfshaft
> route ain't the best way to go since they machine the
> shaft and ruin the temper, giving them an effective lifespan of
> about 3 months.