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need help with my 85 K10 blazer 3.42 rear end

Discussion in 'The Garage' started by brandoblazer, Aug 22, 2002.

  1. brandoblazer

    brandoblazer Newbie

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    ok heres the deal. I have a 6.2 liter k10 1985 blazer with a 3.42 differential ratio. after a brief offroad trip i heard a knockin', so i figured something was wrong. pretty much to some it up the rear differential was torn to pieces litterally. now i need a new rearend. ive heard that the 3.42 ratios are pretty unreliable so i need advice one what i should do. i am contemplating either gettin a new 3.42 rearend. or i am going to try to put a different gera ratio on the blazer such as a 4.10 or 3.73 , but if so what steps to i have to take to change the gear ratio and how much $$$money am i lookin at spending???
    Im running 35x15x12.5 rubbers and i have a three inch lift .

    any advice will be greatly appreciated.
     
  2. dammit32

    dammit32 1/2 ton status

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    i picked up a pair of axles off a 3/4 ton truck in a salvage yard for $300 and most of them come with 4.10 gears and bolt right up to a k5...the technical part of this site has many resources on this and if you have any questions the guys here are great at helping out
     
  3. trailblazer87

    trailblazer87 1/2 ton status

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    I can spot the reason that the rear end was fried already, 35's and 3.42 gears, to run 35's you should get at least 4.10's if not 4.56's, and if you are in the rocks a lot then 4.88's. Junkyard axles are a good way to go. If you can open them up and look inside, look for rust, color of the fluid, condition of the bearings and shims. Axles out of any chevy full size from 73 to 91 and later will bolt in to each other. If you are wondering about gear ratio's, there should be a tag on the diff. with the type of axle (10b, 12b, dana44, dana60, etc.) and gear ratio. Sounds like a good time for an upgrade, a decent set can be picked up for anywhere from $200 to $500. Don't forget about brakes, brake lines, vent hoses (might as well extend them). If you looked hard, you might be able to find a set of rockwells for a few hundred bucks. If you do go beefier, you might also have of get a heavier drivline and bigger u-joints. Chevy used to ship axles with detroit lockers in them, you may get lucky and save your self $500 that way. Good luck.
     
  4. Roy2099

    Roy2099 Registered Member

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    I have 3.41 with 35x12.50, and they are perfect for me!!

    With the transfer in Low they are just Fine.

    Brandoblazer, if you prefer power for 4x4 and loose top speed go for the 4.11, if not stay where u are.
    /forums/images/icons/grin.gif
     
  5. brandoblazer

    brandoblazer Newbie

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    thanks for all the useful info.. i did go to all the salvage yards in the atlanta area but didnt find one good axle, except one down town for 850 and one that i can get shipped from alabama for 900. which is a whole lot more than i wanna spend so i think im gunna keep searchin for a 4.10 at the salvage yards.
     
  6. 4x4k20

    4x4k20 1/2 ton status

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    Location:
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    a buddy of mine has a 3;42 rear out of a k5 that he wants to sell here in barnesville ga he bought it and was told it was a 3;73 but he opened it up and found that its a 3;42 so he has it for sale if you are intersted let me know i am sure he doesnt want much for it
     

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