I hear that the 4 bangers do not have the torque that typically breaks the axle.
Its not the torque that breaks an axle, its the combination of friction and weight. I broke a D35 axle climbing a rocky edge, locked at both ends, 4.88s, and 34" LTBs. I tried creeping up, but alas couldn't get the rear tires to bite and pull me up. So I tried to bump it a little. I bumped and rather than climb it bounced and then it happened. I've since swapped to a 8.8.