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  1. mikejax87k5

    mikejax87k5 Newbie

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    how can i find out if i have positive traction on my 87 k5?
     
  2. TX Mudder

    TX Mudder 1/2 ton status

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    Do you mean posi-traction, the trademark for GM's limited slip differential?
    Jack up the rear axle and put two jackstands under it. Put the tcase in neutral and turn one of your wheels with your hand. If the wheel on the other side of the axle turns in the opposite direction, you have an open differential (no posi). If the wheel turns in the same direction, you have a limited slip differential (so, yes.)
    -- Mike
     
  3. 90K5

    90K5 1/2 ton status

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    Also sometimes if they turn opposite directions its just a worn out posi

    90K5
     
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    There might be a tag atached to the cover if it is a posi. Its supposed to be there to let you know to put posi additive in the diff fluid.
    Mostly the tag gets left off after the first service.

    Rene

    [​IMG]
     
  5. bigdaddy89

    bigdaddy89 1/2 ton status

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    Look inside your glove compartment and see if you have a G80 with the other codes. If so, then you have a limited slip diff.
     
  6. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    the ones on my 79 turn oposite directions when both rear wheels are off the ground but I can assure you it locks completly when under load and leaves two beautiful black marks on the pavment as it vaporises the BFG's. It pulls like mad off road and at most only alows the wheel without traction to make 3/4 of a reveloution before it locks down and pulls.

    Diging it in the dirt with my K5's
    Grim-Reaper
    http://grimsk5s.coloradok5.com/
     
  7. Blazer1970

    Blazer1970 1/2 ton status

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    If it is a factory locker in '87 it is a Gov-lock. This locking differential acts just like an open diff unless a wheel spins fast enough to kick in the governor, and lock the clutches. If you do the test where you jack up the back end, the other wheel will always spin opposite, just like an open diff.

    Tim

    1970 Blazer CST 4X4 350 SM465 NP205
    1987 Suburban 4X4 350
    1988 Chevy Pickup 4X4 350
     
  8. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    Right,while the old "jack it up and spin one wheel" works on the real Posi-traction, and all other clutch type L/S, too. It won't tell you a thing about a Gov-loc. You can check the glove box, like someone said, or just pull the cover and look inside. Now would be a great time to change your gear oil, too. If you see side and spide gears, its open. Grim or someone else who knows can tell you what the Gov-loc looks like.
    Jim '80 GMC.

    It's a Wheelbase thing, You're Jeep wouldn't understand!
    http://www.bigjbear.coloradok5.com
     
  9. Blazer1970

    Blazer1970 1/2 ton status

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    A Gov-lock does have all the normal differential gears. That's why it is so good at emulating an open diff. It just has added clutches and actuating means to lock the side gears together when a wheel spins.

    Tim

    1970 Blazer CST 4X4 350 SM465 NP205
    1987 Suburban 4X4 350
    1988 Chevy Pickup 4X4 350
     
  10. River

    River 1/2 ton status

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    I have a 1990 K5 and when a jack it up and spin one wheel the other one turns the opposit direction. Means this it is not a limited slip? (the rpo codes say`s G80)

    Greetings from Amsterdam,

    River `90 K5, 350, TH700R4, NP241, "33, 3.08, 10 bolt F, 10 Bolt R
     
  11. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I had the cover off of my old 10 bolt (7 5/8") in my S-10 with the gov lock. It looks like a little cuckoo clock in there (very weird) some sort of centrifugal mechanism?

    River if it says G80 on the glovebox it is most likely a Gov-Lock (unless the rear diff has been swapped, or glove box door for that matter) When you jack up the rear with a Gov-lock the tires will spin in OPPOSITE directions.

    Rene

    [​IMG]
     
  12. River

    River 1/2 ton status

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    I did a test, drove in the dirt till a get stuck (2WD) then checked if 2 wheels where spinning in the same direction seems the gove-lock is working.

    Is there also a gove-lock in the front ?

    Greetings from Amsterdam,

    River `90 K5, 350, TH700R4, NP241, "33, 3.08, 10 bolt F, 10 Bolt R
     
  13. Blazer1970

    Blazer1970 1/2 ton status

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    No, they don't put 'em in the front.

    Tim

    1970 Blazer CST 4X4 350 SM465 NP205
    1987 Suburban 4X4 350
    1988 Chevy Pickup 4X4 350
     
  14. Executioner

    Executioner 1/2 ton status

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    Well do your what to know for sure(Fact), or just a best guess.
    If you what to know for sure, its gone cost you allot of $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ ( LOL )
    Just remove the cover, can't get any simple that that !
    Good luck
     

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