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How to tell gearing ratio without pulling cover??

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 1990SilveradoK5, Jun 19, 2001.

  1. 1990SilveradoK5

    1990SilveradoK5 1/2 ton status

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    I am going to look for a set of axles for my 1990 and want to be able to determine what gearing I am looking at in the salvage yard with out tearing every truck apart.

    Is their an easy way to tell the axle ratios without pulling the covers?

    Gone Large and Loving It.
    Keith
     
  2. MUD_SPEC

    MUD_SPEC Registered Member

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    Jack one side of the axle up and spin the wheel one time. Count how may times the driveshaft goes around during one spin of the wheel. This is the approx. gear ratio.
     
  3. ftn96

    ftn96 1/2 ton status

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    Most decent yards will already have them marked. But the safest way is to take it off. But the note from Mud will give you a close guess-timate.

    Also, go to the specs page here at CK5 and look back a few years before 90 and see when the 30 spline axles started, then when you go to the yard you dont have to limit yourself to just a 90. You can go back even further than that but you go back to the 28 splines which are a bit weeker than the 30's but will work if it is complete. You'll just have to remember that your normally 90 30 splines are now 28's...
    Good luck.

    Steve Fox for President, 2004.
    Jimi Hendrix was re-incarnated in 1990 as my....JIMI
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  4. Itali83

    Itali83 1/2 ton status

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    If the trucks are unmolested check the glove box for these codes: GU2 = 2.73 GU4 = 3.08 GU6 = 3.42 GT4 = 3.73 GT5 or GT8 = 4.10 AND G80 = gov. Lock.
    Ben 87 Jimmy
    <A target="_blank" HREF=http://www.bens87toy.coloradok5.com>http://www.bens87toy.coloradok5.com</A>
     
  5. 1990SilveradoK5

    1990SilveradoK5 1/2 ton status

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    OK the 30 splines were introduced in 1989 according to the specifications page.
    Was this across the board?
    If so I will be able to look for the axles under Blazers, Subs, and Trucks and they all should have 30 splines after 1989, correct?

    I know most of these questions are somewhat repetative but I just want to make sure I get what will work as is, no modifications or extra parts to purchase to make them work for me.

    Thanks in advace.

    Gone Large and Loving It.
    Keith
     
  6. Executioner

    Executioner 1/2 ton status

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    Good luck, the answers so far will get you close, but if you need to be right on, you know the drill............
    Since you don't want to remove the cover, how much are you willing to pay for the tool ?
     
  7. 1990SilveradoK5

    1990SilveradoK5 1/2 ton status

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    Executioner
    What do you mean by "how much are you willing to pay for the tool?"

    I am just wanting to have an approximate ratio for the axles prior to having them cut off the truck. If I have to wrench it myself to find the ratios I will spend weeks in the yards. Yes not all a bad thing but the last time I spend an hour in the yard in the pouring rain and last winter I had about an inch of snow on my head by the time I found a washer resevoir for my truck.

    Gone Large and Loving It.
    Keith<P ID="edit"><FONT SIZE=-1>Edited by 1990SilveradoK5 on 06/19/01 06:14 PM (server time).</FONT></P>
     
  8. Executioner

    Executioner 1/2 ton status

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    Well it goes something like this, you can pull the cover, and know for sure the ratio, or you can spend
    a couple hundered and buy the tool. Or you can get close if your lucky, say 3:1, 4:1, 5:1..............
    Good luck, I think your gonna need it.
    P.S. Sorry if you don't like the FACT"S, maybe you can do something to change them, but I dought it.
     
  9. 90K5

    90K5 1/2 ton status

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    When you jack up the truck and spin the tire, you have to go 2 revolutions to get the ratio.

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  10. Executioner

    Executioner 1/2 ton status

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    Kind close, but it may not alwasy be the case.
    Have you heard of diff that have 3 spider(pinion) gears.
    (Not pinion as in ring and ping, but as in spider/sige gears).
     
  11. yunit

    yunit 1/2 ton status

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    My truck has these codes. 9G80 & 9GU6. Is the Gov any good?

    1978 K5, Palisades Park, NJ 07650
     
  12. 90K5

    90K5 1/2 ton status

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    Gov-lock probably doesn't work after 23 years.....they aren't anything special

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  13. thatK30guy

    thatK30guy 1 ton status Premium Member

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    <blockquote><font size=1>In reply to:</font><hr>

    or you can spend
    a couple hundered and buy the tool.

    <hr></blockquote>

    WTF? What is this so-called "tool" you are talking about?

    <font color=red>I m so we Todd did.
    I m sofa king we Todd did.</font color=red>
     
  14. 90blzr

    90blzr 1/2 ton status

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    WTF? is right!! Why does this guy always have to have an f'ing problem with everyone's advice but his own. Maybe he should just set up his own board since he knows everything. Some people dont know it all dude, some of us are just learning as we go. Thats what the board is here for, not to try to make everyone else look like an @ss!! Give everyone a break man!! WRONG! NOT!! CHANGE THE FACTS, WTF????????????????!!!!!!!!!!!!!!!!!!!!!!!!!!!!
     
  15. BlueBlazer

    BlueBlazer 1/2 ton status

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    What is the tool you ask. Its the baseball bat that you use to beat the living crap out of the "Executioner" for being such a son of a b!tch.
     
  16. 90blzr

    90blzr 1/2 ton status

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    ROTFLMFAO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
     
  17. DMK

    DMK 1/2 ton status

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    I like that![​IMG]
     
  18. 1990SilveradoK5

    1990SilveradoK5 1/2 ton status

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    Thanks guys, I was feeling the same way when I read his response but did not want to vent and sound like a prick when someone is giving advice.

    But I do agree with the WTF responses, If you ask me it sounds like Executioner is a tool, if you know what I mean.

    Gone Large and Loving It.
    Keith
     
  19. Don't worry about him, his social skills are lacking. I try not to read his responses but I can't help it. He is just trying to stir up trouble. Hey maybe he is "Buttman" in disguise. I know that guy is in here somewhere! LOL



    '84 K5

    Chevy in my blood.
     
  20. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Occasionally Executioner makes a good point. He's just abrasive about it.
    The fact is that with all the different types of diffs out there with all the different possible traction aids it really is a big chance you're taking if all you're gonna do is rotate a tire.

    I would try and figure a ballpark by rotating a tire, and if it looks like it may be the ratio you're looking for then pull the cover to confirm the ratio and check for the condition of the diff. Glove box codes are useless unless you've owned the truck from day one.

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
     

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