What causes the bolt heads to snap off carrier to the ring gear?

Guirey

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What causes the bolt heads to snap off carrier to the ring gear? Took my cover off today just for an inspection and found 4 bolt heads in the bottom of the diff. No looks chewed up but what would cause the heads to snap off like that? 97 TJ Sport 4.56 rear end with a Detroit True Trac.

Thanks
Terry
 
I snapped a few off pulling a van out of the sand. My tires were on the pavement. 5.38s. Something had to give.
 
Ring gear bolts were likely not torqued to spec and/or missing loctite
Good call, no loctite, 5 of the 8 heads snapped off, once I took the other 3 out I was able to use my fingers to take out the busted bolts. New bolts are on order and will use red loctite. Glad the heads fell to the bottom, nothing got chewed up. Thanks for your help.
 
Overtorqued probably when the lockers were put in. Easy to do if there is oil in the treaded hole or on the bolts - add in repeated heat and load cycling. No loctite they would loosen and the joint would slip but the bolt heads wouldnt snap off. Might want to check your front axle too since it was likely the same installer and procedure.
 
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I had that happen with a Yukon Zip when I broke my locker and gears (maybe a shaft too). Yukon actually sent me a replacement locker. It ended up being my final straw on my Dana 30. Replaced with a Currie 44.

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Ring gear bolt failure on Dana 35s (and Ford 8.8s) is not uncommon and is what led Dana to come out with the "super" 35 which has larger ring gear bolts. Dana 44 failures are typically from over torque or lack of thread locker. Use good bolts, Red loctite and proper torque is the best you can do.
 
Overtorqued probably when the lockers were put in. Easy to do if there is oil in the treaded hole or on the bolts - add in repeated heat and load cycling. No loctite they would loosen and the joint would slip but the bolt heads wouldnt snap off. Might want to check your front axle too since it was likely the same installer and procedure.
front is next after I finish the back this weekend. thanks for your reply
 
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When too much torque is applied to the ring gear, the bolts will stretch very slightly. This causes you to lose preload on the bolts. That means they are now slightly loose. Without a secondary locking mechanism such as a thread locker (Loctite) or safety wire, the bolts will start to back out. Having the proper torque is very important. Torque it to less than spec and you it will be much easier to lose preload.
 
When too much torque is applied to the ring gear, the bolts will stretch very slightly. This causes you to lose preload on the bolts. That means they are now slightly loose. Without a secondary locking mechanism such as a thread locker (Loctite) or safety wire, the bolts will start to back out. Having the proper torque is very important. Torque it to less than spec and you it will be much easier to lose preload.

The funny part about all that is how many gear setters who do it for a living and warranty their work don't use a torque wrench. I actually know at least 4 gear setters and none of them use a torque wrench on the ring gear or carrier bearing cap bolts.
 
The funny part about all that is how many gear setters who do it for a living and warranty their work don't use a torque wrench. I actually know at least 4 gear setters and none of them use a torque wrench on the ring gear or carrier bearing cap bolts.
I have worked with a few gear guys over the years that were like that. Could do the whole job by feel including pinion preload.