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..I thought my 14 bolt was un-breakable...

Ryan B.

Ryan B.

3/4 ton status
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3 busted teeth on my 14boltFF 4.56 pinion.. with 35's on the street. /forums/images/graemlins/blush.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/dunno.gif /forums/images/graemlins/screwy.gif /forums/images/graemlins/whistling.gif
Was driving normally, accelerating and it hit 2nd, chirp the tires like usual, but followed by a burrurppapapapapapappapapapapa.. i limped it home from work about 8 miles on surface streets...

I have put probably 15K-20K miles on the rearend over the last year...
These are 4.56 Yukon brand gears.. when i took it apart the backlash seemed within spec, it doesn't look like anything loosened up at all... but i found 3 broken teeth in the housing after draining the fluid. /forums/images/graemlins/screwy.gif

So is this my harsh stage 2 shift kit taking its toll? My driving style? Crap gears? Defective gears?
 
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Yukon brand gears

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that could be part of the problem or so i've heard /forums/images/graemlins/dunno.gif
 
Hey Ryan, do remember me from Hollister this year in the Red Suburban? I broke the spot welds that hold the axle tube to the center section, twisted the tubes in the center section, and bent it. Nothing happened to my Yukon gears. I had my gears transfered from the broken 14 bolt to my replacement housing. I had the axle tubes welded to the housing and a I made an over the top axle truss. I would put the blame on your driving style. /forums/images/graemlins/whistling.gif
 
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Yukon brand gears

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that could be part of the problem or so i've heard /forums/images/graemlins/dunno.gif

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Guaranteed that is not the problem.

Improper break in? Where was your backlash set? What did your pinion bearings look like?
 
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Guaranteed that is not the problem.

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Nobody can guarantee that that isn't the problem. Even companies with the best QC, and the highest quality have the occasional part slip through that isn't 'right'. It 'might' have been a weak set of gears.

If the wear pattern is cool and it broke on the street with 35's I'd say weak or defective gears could be the problem. Pretty rare to see a 14 bolt failure unless it is really low on gear lube...

Rene
 
yep, followed proper break-in.. backlash seemed fine. bearings were fine. gear pattern was right on. I've put a lot of miles on this gearset and its been fine until a couple days ago... a diff shop i talked to said that breaking a couple of pinion teeth is from shock loading the gears like a hard slam into the next gear, or spinning the tires and biting all of a sudden getting traction.. "you mean like a harsh shift kit?" /forums/images/graemlins/rotfl.gif
I did the same thing to a 12 bolt for no appearant reason a few years back..
 
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Guaranteed that is not the problem.

[/ QUOTE ]

Nobody can guarantee that that isn't the problem. Even companies with the best QC, and the highest quality have the occasional part slip through that isn't 'right'. It 'might' have been a weak set of gears.

If the wear pattern is cool and it broke on the street with 35's I'd say weak or defective gears could be the problem. Pretty rare to see a 14 bolt failure unless it is really low on gear lube...

Rene

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I am one to never blame the parts until everything else has been investigated. Usually a bad gear set never sets up correctly anyway.

If you believe that was due to shock loading, you need more carrier bearing preload. Your backlash might have been fine until you got to beating on it, when it opened up and sheared the teeth off.

Since it happened on a shock load, I'd say that this is the likely culprit.
 
Like I said on the nor cal board Ryan, usually "normal driving" doesn't involve chirping tires, especially in 2nd gear... If you do that as "normal driving" I doubt anythings going to last too long under that truck /forums/images/graemlins/shocked.gif
 
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Like I said on the nor cal board Ryan, usually "normal driving" doesn't involve chirping tires, especially in 2nd gear... If you do that as "normal driving" I doubt anythings going to last too long under that truck /forums/images/graemlins/shocked.gif

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I'd say that's rather normal. /forums/images/graemlins/rotfl.gif
 
BaWWWWWWAAAAAAAA CHIRP!!!

/forums/images/graemlins/dunno.gif /forums/images/graemlins/whistling.gif /forums/images/graemlins/rotfl.gif
 
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So is this my harsh stage 2 shift kit taking its toll? My driving style?Crap gears? Defective gears?


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/forums/images/graemlins/whistling.gif /forums/images/graemlins/whistling.gif /forums/images/graemlins/whistling.gif
/forums/images/graemlins/waytogo.gif /forums/images/graemlins/waytogo.gif /forums/images/graemlins/waytogo.gif

<font color="white">Now can you tell me why every jack***I have on ignore had to reply to this thread ? </font>

/forums/images/graemlins/histerical.gif /forums/images/graemlins/histerical.gif /forums/images/graemlins/histerical.gif
 
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Usually a bad gear set never sets up correctly anyway.

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That would be true if the grinding of the teeth shape were off. NOT true at all if it were a heat treat defect.

Witness the early 1903 Springfield bolt action service rifles. HT was off and you could not tell until it killed the shooter or you whacked it with a hammer and watched it shatter like glass.
 
Yukon is Chinese for CRAP! Remember the old saying “you get what you pay for.” It’s was either gear setup of Chinese Crap. Welded Diff or not you aren’t putting enough load on the R&amp;P no mater how hard you shift or drive to cause breakage if you’re set up is right and you have quality gears. We put more shock loads on a R&amp;P in 1000 miles of racing than you could in a lifetime on the street. I Wet Mag every set of gears after a race and when I do find cracks, they are at the root of the gear. It’s hard to tell from the pictures, but it looks like they broke higher on the face of the gear. What did the ring gear look like? While I would never race on Yukon Gears, the problem was more likely setup or change in setup due to wear.
 
Wow... It looks alot worse then what you described. /forums/images/graemlins/doah.gif

BTW- See you in Hollister tonight /forums/images/graemlins/bow.gif /forums/images/graemlins/woot.gif /forums/images/graemlins/waytogo.gif
 
Dude, its the TPI! My goals to bust my 14 bolt! We actually got a 14 bolt in at work yesterday for broken pinion. So guess your not takin the k5 to hollister?
 
Looks like its time to upgrade to 10 bolts /forums/images/graemlins/rotfl.gif

I have a buddys truck coming into my shop this weekend to swap in a new 14 bolt.
His pinion looks like yours. He also broke his spyders.
Funny thing. He and I were out cutting wood when he broke it.
He had his K2500 loaded. I was following him out in my K5 towing a trailer with a cord (2000lbs) loaded on it.
He broke his 14 bolt on the same ditch and little hill I drove over no problem.
Good thing I had my trusty K5 on its mighty 10 bolts /forums/images/graemlins/waytogo.gif To get us and the wood out. Went back larer with a car trailer and got the truck.
 
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So is this my harsh stage 2 shift kit taking its toll? My driving style?

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yes /forums/images/graemlins/deal.gif
 
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