dana 30 went BOOM

You guys place too much emphasis on gear breakin in the wrong scenario. Gear breakin is VERY important for high speed driving (street), not so for crawling. You dont see guys with hubs doing much more than driving a few miles on the street(IF you can even do that) adn changing the gear oil after the first trip out. Its VERY important for you street driven guys with NO hubs and Higher highway speeds.
 
ChuckD said:
What size tires are you running?



Ryan did my 30, so far working great with 4.88 Yukons.
Click to expand...


33" muds. I don't see why the ring gear would be a weak link in my setup. If this breakage was from shock then why didn't some thing else go first if the gearset was not defective?
 
scorpio_vette said:
i personally haven't broken gears like that, but it almost looks like somebody beat on a set of brand new gears and sheared them off before they got hardened.
Click to expand...

the gears should be hard right out of the box... pretty sure the heat treatment woud be done at the manufacturer. breaking in the gears is all about creating a smooth contact and wear surface between the teeth. material is worn off and compressed. the lube keeps the gears from getting too hot and prevents them from getting hot enough to go through a change in hardness or gall.

the pic reminds me of when i accidentally dropped the clutch and stripped off a few teeth on my D35 R & P.
 
scorpio_vette said:
here is a pic that xXJx send me.

blownD30.jpg
Click to expand...
is it me, or does that seem like a large gap in the locker?
 
I think one thing that we need to consider here is that he broke the ring gear "on road" pulling away from a stoplight, where I am guessing he was in two wheel drive... No strain should have been on those gears at all... sure they are turning, but no power from the engine should have been turning them... this one has me puzzled... curiously, can you remember whether it was a nice easy stop at that stoplight or did you jam on the brakes or anything?
 
I thinks its pretty clear that It "ate itself", meaning either one of the teeth came/sheared off causing it to be caught between pinion and ring gear and cause further damage, or something else inside the diff couldve gotten caught in between
 
jjvande said:
the gears should be hard right out of the box... pretty sure the heat treatment woud be done at the manufacturer. breaking in the gears is all about creating a smooth contact and wear surface between the teeth. material is worn off and compressed. the lube keeps the gears from getting too hot and prevents them from getting hot enough to go through a change in hardness or gall.

the pic reminds me of when i accidentally dropped the clutch and stripped off a few teeth on my D35 R & P.
Click to expand...

well i don't know the process of how gears are made/manufactured, so i'm not saying you are wrong. but i do find it interesting that most gear sites have this article in their tech/help section.

http://www.ringpinion.com/content/technicalhelp/default.asp?pid=122

The greatest damage to a new gear set results from running for ten minutes or more during the first 500 miles when the oil is very hot. Any heavy use or overloading while the oil is extremely hot will cause it to break down and allow irreversible damage to the ring & pinion.

In order to make them run cooler and quieter, new gears are lapped at the factory. However, they are not lapped under the same pressures that driving creates.
Click to expand...
 
Last edited:
Breaking them in also work hardens the gears, which is probably the most important reason for breaking them in.
Front gears hardly ever get work hardened, as they rarely have power to them.
While this whole "easy driving" scenario may be legit, if someone brought back a Jeep, that I did, with gears as blasted as those, I'd have to question the validity of the story.
That actually looks like a picture of a few others I've seen's fronts and I guarantee they weren't just pulling away from a stop light in 2wd.
 
jjvande said:
is it me, or does that seem like a large gap in the locker?
Click to expand...

After reading your comment I went and looked at the locker and noticed that one of the springs for the lockrite was missing.......it used to be there........


Digging out the little pieces of spring took a few minutes mabey that's what did it. You think???,
 
my local shop said to me when i regear ill have to run my stock tires for 500 miles to break them in.

then put on the meats.

good luck
 
jjvande said:
is it me, or does that seem like a large gap in the locker?
Click to expand...

After getting your comment I went and checked the locker and noticed a spring was missing and then I dug all the little broken pieces of spring out of the housing. Mabey that's what did it. Wow a little spring did so much damage.
 
Probably not the spring, but one of the pins that are supposed to be in there with the springs would sure as heck do that.....................Bingo
 
I don't believe a missing spring would cause a gap to be that large, the springs push those pieces apart, not together. If that's a lock-right, the stock thrust washers (between the case and the lock right on both sides) need to be in there. There should be a gap check block that came with the lock-right. but yes, it does look a little big.
 
So, the pins fell out of the lockright, got caught in the R&P and it ate itsef up.

Mystery solved.
 
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