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Best diff gears for 33's??

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by ErikH, Jun 10, 2001.

  1. ErikH

    ErikH 1/2 ton status

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    Best diff gears for 33\'s??

    Yet another question...

    What diff gears should I install to run 33x12.50's with a mildly modified 350? The stock 3.07's are too tall for 33's in my opinion.

    Also, when I replace the ring/pinion, I'd like to replace the stock posi, which actually still works, but what should I go with? I don't have a big budget. How much can I expect to spend replacing gears front and back with a new posi in the back? Obviously I'm not doing this job myself.

    Thanks for any help.

    Anyone have advice
     
  2. BobK

    BobK 1/2 ton status

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    Re: Best diff gears for 33\'s??

    There was a post about this a while back.I think the concensus was 3:73 gears with a 350/350 combo (eng+tranny combo).My guess is approx.$700-$1000 for the gears,posi and labor to put in.Again that's a guess.

    <font color=green>BobK<font color=green>
    <A target="_blank" HREF=http://www.zing.com/picture/p8947726813026de684f60e0bd6f3fbfe/fe8f5839.jpg>http://www.zing.com/picture/p8947726813026de684f60e0bd6f3fbfe/fe8f5839.jpg</A>
     
  3. UseYourBlinker

    UseYourBlinker 1 ton status

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    Re: Best diff gears for 33\'s??

    I went from 3.07 to 3.73 also with 33/12.5R15 tires...Very happy with them.


    <A target="_blank" HREF=http://community.webshots.com/user/vwryda>http://community.webshots.com/user/vwryda</A>
     
  4. Triaged

    Triaged 1/2 ton status

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    Re: Best diff gears for 33\'s??

    I have 33's and 3.73's and it feels perfect to me. For the posi in the rear are you looking on replacing it with a locker or another LSD? If a locker go Detroit. If a LSD go Detroit Trutrac (IMO).

    '71 Blazer CST with alot of rust
     
  5. Steve_Chin

    Steve_Chin 1/2 ton status

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    Re: Best diff gears for 33\'s??

    I'm going to go with 3.73:1 gears. A friend is going to put 4.10:1 gears in. I'm running an NV4500 and my friend will be running one in a couple of months.

    The Grand-Poobah of all limited-slips is the Torsen, but they don't make one for the 12-bolt truck differential (they are open to requests). I like Eaton's clutch-type differential and I hear that ARB is the only way to go for an air locker, with Detroit being the way to go with a conventional locker. None of them are really cheap. Why not just get a thick ring gear gearset and rebuild your existing carrier? That's what I'm going to do unless I can somehow con Torsen into building a carrier...
     
  6. Triaged

    Triaged 1/2 ton status

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    Re: Best diff gears for 33\'s??

    The Torson is the best LSD out there (Heck they use 3 on a Hummer) but the applications are limited (only ford 9" and a few others). The TrueTrac is a copy of the torson and has applications for many 4x4's. The TrueTrac is in between a locker and a clutch type LSD in offroad performance and handles better on the street like an open diff. While I would generaly stay away from "copy cat" products the TrueTrac is available for applications that the Torsen is not and is cheeper than a Torsen (by alot) IMHO



    '71 Blazer CST with alot of rust
     
  7. ErikH

    ErikH 1/2 ton status

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    Re: Best diff gears for 33\'s??

    Other than knowing how they generally work, I don't know much about rebuilding differentials.... So I'm not sure how to answer your question about rebuilding the carrier. What is the "carrier?" I've only heard that diff work can be complicated... is this always true, or are there jobs an average home mechanic can tackle? I'll tackle anything if it's even marginally do-able.

    And thanks for all the responses. At least I know what ratio is best.
     
  8. Burt4x4

    Burt4x4 3/4 ton status

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    Re: Best diff gears for 33\'s??

    I did my own ring & pinion job. It took me a long time to complete it too. I did not work on my rig every day but every weekend and took 4 weekends to finish front and rear.
    With the right tools and allot of time and the proper research it can be done at home. You only save a few hundred bucks by doing it yourself so if you need it done in a timly manner and you can't spend 30 hrs straight on it then find a good shop and have it done in 6hrs. I did it more for the experiance well and the fear of having some stranger doing a half a$$ job on my rig[​IMG]
    Good Luck

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
    <A target="_blank" HREF=http://www.burt4x4.coloradok5.com>http://www.burt4x4.coloradok5.com</A>
     
  9. Steve_Chin

    Steve_Chin 1/2 ton status

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    Re: Best diff gears for 33\'s??

    The carrier is the rotating assembly inside of the differential housing. It is sometimes called the differential. Rebuilding the carrier itself is not too involved a process, but you need a few special tools. All in all, it's still cheaper to rebuild your existing carrier than it is to get a new one (and if you have a really good builder do the job, he can set it up with extra preload without harming the differentiating characteristics of the unit).

    I've done a couple of gear changes and I'm with Burt4x4 on his opinion: It's easier to have a Pro do it in a day than it is to spend a couple of weeks on it yourself.
     
  10. 71RestoRod

    71RestoRod 1/2 ton status

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    Re: Best diff gears for 33\'s??

    Speaking of the carrier... it's probably worth mentioning that there is a carrier split on the Dana 44 if you go lower than a 3:73, so that would be a good gearing choice if you want to save yourself the cost of a new carrier.
     
  11. Neil

    Neil 1/2 ton status

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    Re: Best diff gears for 33\'s??

    IMO...I you have to ask how to do this..don't attempt it alone. The clearances are the main reason why. With new ring and pinion, you don't want bad lashing/clearances and ruin a new
    piece of expensive equipment at home alone..Good luck to you!..Neil H. Alabama K5 4x4
     
  12. da_burb

    da_burb Newbie

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    Re: Best diff gears for 33\'s??

    On the off chance that you are in the MID-WEST US, I have a complete 71 K-5 Blazer for $1400 with posi 3.73 gears. It has the typical rust for a Minnesota truck. Drivetrain is great, 305V-8, th350, PS/PB. Drive it home. Pictures&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;
    <A target="_blank" HREF=http://community.webshots.com/album/13999124wyUYlPGyfl>http://community.webshots.com/album/13999124wyUYlPGyfl</A>
     

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