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Helpful hint for extra strength in a 12 bolt!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Emmettology 101, Oct 26, 2000.

  1. Emmettology 101

    Emmettology 101 3/4 ton status

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    Hello all, just though I would share this with everyone.

    A truck 12 bolt has a 1.438" pinion stem and Richmond gears from Jegs cost $169.99.
    A car 12 bolt has a 1.63x" pinion stem and Richmond gears from Jegs are $137.xx

    You can use the Car gears in the truck 12 bolt with the use of a special pinion bearing from Timkin.

    The bearing part number is : 24721
    and the race part number is: 24780

    This will give us roughly .200" more and add a little strength and save about $30 on gears!

    Hope this helps someone!

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; http://emmett.coloradok5.com
     
  2. FWP

    FWP CRS

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    Thanks, I'll save this post. If my 12 bolts go up in smoke, I'll be armed with more ideas.

    <font color=blue>Maverick</font color=blue> <font color=red>CH 4 or 35</font color=red>
     
  3. Wheels

    Wheels 1/2 ton status

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    Good info. I plan on changing out front and rear after the first of the year.
    Thanks.
     
  4. 89Jimmy

    89Jimmy 1/2 ton status

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    Didn't you have a post about using a 10 bolt yoke on a 12 bolt pinion to up the u joint size? Does it fit the truck size or the car size? Wasn't there a special seal or bearing involved on that one as well? I searched the posts but didn't find it.
    John

    So Much to do, So LITTLE cash.
     
  5. Emmettology 101

    Emmettology 101 3/4 ton status

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    One more note on this, the bearings are not avaiable from normla parts stores, you have to get them from a Bearing wholesaler. And as with anything shop around. I called four bearing places today and I got prices from $10.57 - $19.82 for the same bearing!

    If you cant find a place near you, let me know I can pick them up and ship them out to you!

    And remember these are TIMKIN bearing part numbers.

    :)

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; http://emmett.coloradok5.com
     
  6. Emmettology 101

    Emmettology 101 3/4 ton status

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    They are both listed as a 30 spline pinion so I would imagine that they would be the same, but I will double check and post what I find out.

    Well I called before hitting continue:

    You would use the same Yoke and pinion seal as used in the truck, so yes you could use the 10bolt yoke in this application.
    However you do need to use a different pinion seal when using a 10 bolt yoke on a 12 bolt rear. i will have that Pinion seal number for you tomorrow.



    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -> http://emmett.coloradok5.com
     
  7. Brady

    Brady 1/2 ton status

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    What was the deal on the 10bolt yolk.I thought the 12 bolt and 10 bolt used the same U-joint?What year would this be from or is it all 10bolts?Brady

    '73Beautiful Disaster
     
  8. jcg

    jcg 1/2 ton status

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    Wow, your timing couldn't be any better. I'm getting ready to swap in a 12 bolt that I'm rebuilding right now. Between the cheaper gears and the discount I get on bearings directly from Timkin (through my race team), you just saved me some cash!! [​IMG] Thanks! Time to make some calls tomorrow.

    Joe
    RIT Mini-Baja http://www.rit.edu/~bajawww
    Team Mudnuts http://www.mudnuts.org
     
  9. Emmettology 101

    Emmettology 101 3/4 ton status

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    There are 2 different yokes for a 12 bolt. one is small ad one is large. The 10bolt uses the same yoke as the Large 12bolt.
    So some 12 bolts come with the small yoke and either you buy one of those expensive two different sized u-joints or buy a new yoke.
    You can just go buy a large 12 bolt yoke or you can buy a 10 bolt yoke and a new pinion seal.
    A very reputable rearend shop told us about this.
    The 10 bolt yoke is actually a little thicker than the 12 bolt yoke so that is the reason for a different seal and it adds a little strength!!!

    Oh and I forgot to get that pinion seal number.

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; http://emmett.coloradok5.com
     
  10. BurbinOR

    BurbinOR 3/4 ton status

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    Great info, Mike.

    Man, I am missing one thing about PA..........QUAKER STEAK AND LUBE!!!!!!

    <font color=black>'79 - 406 TPI -<font color=orange> K5#5 - <font color=blue>See it at---&gt;http://www.blazzinor.coloradok5.com
     
  11. Emmettology 101

    Emmettology 101 3/4 ton status

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    Funny thing is that I dont get down there much, their food is too expensive and so is their beer! :)

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; http://emmett.coloradok5.com
     
  12. Emmettology 101

    Emmettology 101 3/4 ton status

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  13. mudfanatic

    mudfanatic 1/2 ton status

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    hey when you get that pinion seal number please post it, I am building a Dana44 strengthening database in my 4x4 file[​IMG]
    Thanks in advance,
    Dan

    <font color=red>get involved with land issues or lose the land</font color=red>
     
  14. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    Before anyone gets too carried away here, keep in mind that if the pinion uses the same yoke between the car and truck gear set, there is NO STRENGTH GAIN. The weakest point is the neck to the splines where the yoke fits on, so the car gears merely use a different bearing. It may be worth the switch to save a few bucks, but the strength gain just isn't there.
    As for the yoke sizes, the 10 and 12's do interchange, so you can switch some ujoint sizes, and there is a 1350 yoke available so you can go to the biggest reasonable size joint available. It does take a different seal, but it's pretty available.
    I have heard of some roundy round racers and drag guys breaking pinion shafts, but in a 4wd, the axleshafts seem to be the weak point with gear sets less than about 4.88-ish.
    Hope this helps
    Stephen Watson
     
  15. keith

    keith 1/2 ton status

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    Stephen is right. Also you may run into carrier problems. The carrier does not always fit the same from a car to a truck. I talked to a guy that does nothing but rearend work and he said it is a pain in the ass and not worth the trouble for $30. It would suck to buy these gears and go to have it done and the carrier is the wrong series and they want to sell you a carrier for $300. You would need to know alot more about your set up and if everything matches.
     
  16. Emmettology 101

    Emmettology 101 3/4 ton status

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    I talked directly to Richmond about this. I took it for granted that everyone would know about the series on carriers. You would just buy the gears for the carrier you have and use your truck carrier.
    But whoever is selling you a carrier for $300 is ripping you off for an open carrier!!!!

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -> http://emmett.coloradok5.com
     
  17. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    I actually ended up with some weird stuff going on setting up the 12 bolt van housing for my K5. One of my nice adjustable side shim packs was too thick with no extra shims in it. We had to turn about .012 to .015" off to set the gears up in the housing. Turns out this was a strange van thing, but the gear rep I talked to asked right away if it was a car or truck axle, like it could be a problem. I don't know if using a car gear set would make a bit of difference in this case though. It's entirely possible that the carriers are close for most gear sets and housings, but enough off to be a pain for others.
    Some of this falls under basic gear work with some Murphy thrown in, but it's good to know as much as possible what you're getting into.
    Stephen Watson
     
  18. keith

    keith 1/2 ton status

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    Carriers are expensive. Granted most people don't go to the junk yard and hunt one up. We are the exeption to that rule. If someone comes in to a rear end shop and has a busted carrier try going to the dealer and getting a new carrier. In some instances like Stephen and his van rear end those things are very different from year to year and can be hard to find the right carrier. I'm just stating what I see every day. My friend has a shop and thats what he does. So people come in and wouldn't want to get a used part. Remember I'm talking about all cars not just 4x4's. Gear work can be funny on some vehicles.
     
  19. Emmettology 101

    Emmettology 101 3/4 ton status

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    I can get one for my 12 bolt and a 44 for about $60 each brand new.

    But I know what you mean about gear work being funny in some vehicles! :)

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; http://emmett.coloradok5.com
     

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