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Eaton Posi. Does anyone know if it will work on my blaze!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by GRINCH, May 18, 2002.

  1. GRINCH

    GRINCH 1/2 ton status

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    EATON 8.5 30 SPLINE LOCKER/POSI FROM A 1999 CHEVROLET TRUCK.
    I have a 1990 K5 with the factory 10 bolts. I added 4.11 gears and my limited slip went out and have a chance on getting this eaton. Will it work and what's it worth?

    Thanks
     
  2. Pookster

    Pookster 1/2 ton status

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    I have an eaton posi in my 10 bolt rear. However, mine is a 8.5" 28 spine, for 3.73.

    Be sure to get the same gear #, its not like a bolt on locker.
     
  3. TXsizeK5

    TXsizeK5 1/2 ton status

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    I belive in 88 or 89 they went to 30spline 10bolts... it should work but don't take my word for it.
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Yu should be able to check with a reputable shop to se if part #'s are the same for the carrier. I do know that the housing changed somewhere around that vintage, perhaps to denote the change to disks or something, but the housing is not exactly like "ours", and there could have been other internal changes as well.
     
  5. 91K5

    91K5 1/2 ton status

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    You need to make sure that the donor posi is a 4 series if you want to retain your gears. The "series" denotes the numerical gears it runs, a 3 series for 3.08 to 3.73 gears, 4 series for 4.11 to 4.56, etc.
     
  6. GRINCH

    GRINCH 1/2 ton status

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    Not doubting your info, But I have been searching for some time and looking on eatons and other websites and only see the same part # for all 30 Spline units. They say for an 8 1/2 it's #... for 2.76 and up. The 8 7/8 units (never heard of them)vary by ratio.
    Thanks for you input. Here's some info I found.

    Check it out at <a target="_blank" href=http:///www.motivegear.com/eaton/differential_assemblies.html>/www.motivegear.com/eaton/differential_assemblies.html</a>

    Thanks
     
  7. Blazinaire

    Blazinaire 1/2 ton status

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    8 7/8'' = 8.875'' = GM12bolt
     

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