The axle housings cost about $20 each, took about 2 weeks to arrive, and are available in silver or black. Mine are black.
They seem to be identical castings to the factory plastic units, except metal (obviously). They weigh about 7oz empty. I’m not sure what kind of metal they are cast from, but a magnet does not stick to it.
Everything went to together without issue with one exception. The threaded holes for the differential bearing caps were threaded for machine screws in the new axles, and my original screws in my spawn kit were coarse thread. I took a gamble and just used the coarse screws to re-thread the holes. Works fine. All other parts went together exactly like stock. I am still running all the plastic knuckles, chubs, etc.
The truck seems a little more planted as was to be expected. I do notice that it seems to have lost a little “pep” and I am chocking this up to adding nearly a pound of weight. Motor is still running similar temps as it was before. The axles do not seem to slide over rocks as easily as the plastic units, but it’s not bad. Probably better than aluminum.
Just figured I’d post this up as there seems to be very little info on these axles housings around the web.