when you say houseing, is that what this is? 
I just call it a 3rd, i may be wrong haha
Yep. That's a steel third from a Samurai.
As I understand it, you can swap the aluminum third for the steel but as Brently/Purevil71 sez, "aluminum weak, steel strong".
Also, I have heard that the axle spline count on the Samurai is different from front to rear so you would have to take out the side gears from the steel third and put them into the aluminum third.
By the time you have done all this work, you could simply rip out the ring an pinions from the aluminum thirds and install them in the steel thirds with a rebuild kit and end up with strong, reliable differentials.
I am working on a pictorial article fo Acks FAQ describing the transplant process that should be available by the first of June. In the meantime, try a search for
differential at the FAQ (see the link in the signature below) for some good articles on diff teardown and rebuilding.
Hope this helps!
BTW, Brently: I should have everything done except the R&P installation when I show up for the Fabfest so it should be a quick job! I'm bringing my welder and my nifty portable sandblaster! I hope the farm store sells fine grade sand.