AFAIKT there's a bearing in the housing where the stub enters the housing. I think RJ is correct: the other end is positioned by the sidegear which fits in a recess in the carrier. If that recess wears the side gear moves and the axle can rock up and down and wreck or at least open the seal. (Gotta be good for the gear, too!)
No one has access to the SB I mentioned on page 1?
On normal axles, there isn't usually a whole lot of speed differential between the axle and the carrier: only that difference due to the differential action. With the GM CAD the carrier is pretty much stationary and the axle spins at road speed when in 2WD. On the FWD axles I'm familiar with there's a fairly hefty tube extending from the side gear thrust face through the carrier bearing that supports the stub. The outer end of the stub passes through a roller bearing in the housing. Never had a problem with that setup.
I think we may have solved the problem. We threw (a lot of) money at it. The solution looks like an '07 Yukon...
The Constitution needs to be re-read, not re-written!
If you can't handle Dr. Seuss, how will you handle real life?
Current oil burners: MB GLK250 BlueTEC, John Deere X758
New ride: MB GLS450 - most stately
Gone but not forgotten: '87 F350 7.3, '93 C2500 6.5, '95 K2500 6.5, '06 K2500HD 6.6, '90 MB 350SDL, Kubota 7510