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Differential Gear Ratio change question - do I need a new carrier???

Discussion in 'The Garage' started by captaininsano, Jun 7, 2005.

  1. captaininsano

    captaininsano 1/2 ton status

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    I was looking into changing my gear ratio to 4.88 gears on my rig, I have a 10 bolt and a 12 bolt (ya ya I can't afford a dana60 so save it if that is your response). Now that we are past that, I saw anything past a 3.73 requires a new carrier? Is this correct? I believe highly my 78 k5 has 3.08 gears, it was originally an automatic/np203 truck. Now has a SM465/np205 thanks to me. If I need new carriers that sucks. Any info is greatly appreciated! :D
     
  2. captaininsano

    captaininsano 1/2 ton status

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    Also, I have never setup gears, but want to try. What do I need to know, any special advise or experiences?
     
  3. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    As far as I know , 10 bolt 8.5 has one carrier break . 12 bolts though have 3 carrier breaks . You actually have 3.08 front and 3.07 rear . You need a 3.73 and numerically higher carrier ( lower gears ) for your 12 bolt .
     
  4. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    The 10 bolt has 2 carriers, one is 2.56 only and the other does 2.73-5.57's

    The 12 bolt however has 3 carrier breaks and are 2.73 only, 3.07-3.42, 3.73-4.56's

    So, you will need a carrier for the 12 bolt but not on the 10 bolt.
     
  5. sebban

    sebban Registered Member

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    Can you get 4.88 gears on a 10/12 bolt setup? (I have the exact same setup, and plans.. ;))

    As far as I could gather, you could only go to 4.56 gears.
    Please enlighten me! :cool1:
     
  6. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    You can get 4.88's for a 10 bolt but the deepest gears for a 12 bolt are 4.56's
     
  7. captaininsano

    captaininsano 1/2 ton status

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    Well 4.56 would be nice too, anythings better than what I have.

    As for setting them up, should I attempt it or just have a shop do it? I am pretty damn mechanically inclined, but at the same time gear sets are pricey and destroying them would really suck. How difficult is the swap?

    I think maybe I will just try to find a 4.56 12 bolt in a junk yard. I guess another option is a spool, but I drive it on the street still, so not so much an option.
     
  8. captaininsano

    captaininsano 1/2 ton status

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    GM 12 BOLT 8.875" TRUCK RING & PINIONS
    PART # TEETH RATIO
    14022236 40-13 3.08
    14022237 41-12 3.42
    471879 41-11 3.73
    471879X* 41-11 3.73 THICK
    474014 37-09 4.11
    474014X* 37-09 4.11 THICK
    GM12/456 41-09 4.56
    (*these thick gears are designed to fit a 2.76 thru 3.42 carrier)


    I just found this on http://www.usgear.com/tl/gm2.htm So if I understand this correctly I could go with 4.11 without having to change the carrier? The 3.08 carrier would work with the 4.11 thick gears? If this is the case I might just go with this until getting a 14FF.

    I am trying to get more bang out of the 1/2 ton stuff for now until I can afford the 1 ton stuff, but at the same time, I don't want to invest the duckets in the 1/2 ton junk. If the 1/2 ton gear can last me about a year I will be cool I think..
     
  9. sebban

    sebban Registered Member

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    Dito!!!! :P

    So 4.11 it looks like for me too, but I need to save up some cash first.
     
    Last edited: Jun 23, 2005

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