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front & rear diff swap...

Discussion in 'The Garage' started by PsychoticDeadGuy, Jun 29, 2005.

  1. PsychoticDeadGuy

    PsychoticDeadGuy 1/2 ton status

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    i need to swap out a new diff because i grenaded my spider gears and destroyed my carrier. i found another diff with a gear on it but dont know how to read the numbers on the ring gear. mine says 2 GM 3988518 11 41 4 87. i dont know what the other one has on it at the moment but can someone translate this number into a gear ratio? also, how could i get my ring gear off the diff? i have tried a lot of force but the bolts wont budge!
     
    Last edited: Jun 29, 2005
  2. Emmettology 101

    Emmettology 101 3/4 ton status

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    Fromt he numbers posted. Looks like you have 3.73(41 divided by 11) gears and the gears were made in 4 of 87.

    :)
     
  3. divorced

    divorced 3/4 ton status

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    The 11 and 41 are what you need to find the ratio. The 11 means 11 teeth on the pinion, and 41 means 41 teeth on the ring gear. 41 / 11 = 3.73 gears.

    I *think* the 3988518 is the GM part number, and 4 87 is the date code, but I may be wrong on that.
     
  4. PsychoticDeadGuy

    PsychoticDeadGuy 1/2 ton status

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    wow, i guess that was simple, thanx guys. does anyone know if the front 8.5" diff will fit in the rear and visa versa?
     
  5. resurrected_jimmy

    resurrected_jimmy 1/2 ton status

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    could be wrong but I believe they are different
     
  6. 85mudblazin

    85mudblazin 1/2 ton status

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    They will work front or rear. As long as they are both 28 spline 10b's. they changed the fronts to 30 spline I think in 89'.
     
  7. PsychoticDeadGuy

    PsychoticDeadGuy 1/2 ton status

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    so, i can swap the diffs? how is the front held in? i know how to get the rear axles out but how would i do the fronts?
    ps: my k5 is an 87
     
  8. PsychoticDeadGuy

    PsychoticDeadGuy 1/2 ton status

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    hello? can someone help me out? can i swap the front and rear diffs? i need to get this done asap if its possible...
     
  9. Eric M.

    Eric M. 1/2 ton status

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    I think you need to give a little more detail about what it is you want to do. It sounds like you want to put the front (steering) axle in the rear and the rear (non steering) axle in the front ... I know that's not what your doing, but it sounds a little confusing.

    Eric M.
     
  10. PsychoticDeadGuy

    PsychoticDeadGuy 1/2 ton status

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    i am just trying to swap the differential, not the entire housing or even the axle shafts. just the differential. is it possible?
     
  11. 85mudblazin

    85mudblazin 1/2 ton status

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    For the 2nd time YES you can. It isnt as easy as just swapping them. You will have to set up the gears to make sure they are within specs. This is done with a dial indicator and several other tools. Might want to start reasearching.
     

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