Originally Posted by SierraHawk
Apparently Yukon had a bad batch of axle shafts that caused them to come close to bankruptcy.
That's the kind of situation that's just bad for everyone involved.
The axle shafts come with a warranty but only for vehicles that have tires that are up to 32".
Not terribly surprising, and it's not like a single axle shaft is that big a deal, but more so when you get into the larger situation that you're in now. No fun at all. At least the area you're in is pretty.
I'll +1 on counting the splines yourself. I've really only worked with one mechanic that really understands that these vans have been pieced together from unrelated parts. All the others keep making assumptions about one thing based on another.
As others are suggesting, it's worth considering swapping gears just to get parts to work sooner. I actually had to look this up, since I was confused on why folks were suggesting higher spline count axles for more strength. Higher spline count seems to be directly related to axle diameter. More splines == thicker axle.
Good luck! Also, once you figure out the right axle, consider picking up a spare.