Q: I am trying to determine why my cv joint cage failed

There are no technical bulletins for the CV joints failing on the front axles on this vehicle. I can only speculate since I have owned many 4x4 vehicles, both full time and part time 4 wheel drive types. The only time that I have seen the joints break are when they get in a bind, or the boots get torn and the joint gets worn until it comes apart. Did either of these happen to your joint? When I say bind, I mean you had the 4x4 locked in and made a very sharp turn while putting the joint under stress. Other than that, you may have cracked it on another occasion, and then driven it until it broke itself apart. I don’t think you could avoid doing it again, 4x4 is designed to get us out of a situation like being in a mud hole or stuck in sugar sand. I would replace the joint and not worry about if it’s going to break again. As long as the differential is working as it should, meaning is it locking and unlocking correctly, it will most likely be fine. There are a couple technical bulletins for the lock collar inside the differential binding, but it did not say anything about breaking joints, instead stating that it will make clunking noises. If you haven’t had the joint replaced yet, I suggest you have a professional, such as one available from YourMechanic, replace the CV axle and inspect the entire vehicle for any other problems it may have.