I have had this problem myself . I formally did onsite equipment repair using Chevy 3500 duallys . The first was 89 R3500 ( square body style) cab and chassis , the second was 92 c3500 7.4 pick up body , changed to flatbed . I kept the weight of both to just under 10,000 for dot reasons .
They both had 14 bolt w/10.5 ring gears and both suffered from the same constant and ongoing failures of the outer rear axle bearings. Both trucks had heavier springs to compensate for the additional weight , both had the 14k brake system . And what I was able to find out is the 14 bolt was rated for the that amount of weight , but was at the maximum 100% of the time. I had the axle walk out of the rear end a hand full of times , studs break , wheels fall off with almost no warning . Eventually I swapped the entire rear end over to a Dana70 HD that I had the guys at hillbilly wizard set up for me. I never had a problem ever again . Later I discovered that my old axle tubes were flexing and adding additional pressure to the outer bearing causing the problem . I could have welded supports or purchased a truss kit ( such as this )
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The stock 14 bolt has a 3” tube and the dana70 HD has a 3.5” tube ( extra 1/4 thickness ).
I don’t regret changing to the dana70 HD , but in hind site I would have welded on a truss for a less expensive option .
But hillbilly wizard will set up the rear end exactly how you want it including any ratio changes , locking or open dif , spring mounting option because it will be set up for your truck . I did have to have the drive shaft shortened because the Dana 70 HD is larger.