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Axle Code- Part 2

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Can Can, Nov 26, 2000.

  1. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    While looking through my afore-mentioned code book, I found out that I have a limited-slip rear diff. I seem to recall a post a while back about an additive that GM sells specifically made for limited-slip diffs. Is this lube necessary to use, or does it just offer some extra protection? If so, why is extra protection needed?

    Just curious- Do all K5s come with a limted-slip rear end?
     
  2. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    you do need to use the additive because of the clutches that are in the limited slip unit

    s.smith 77blazer lookin 4 mud
     
  3. Cavalry

    Cavalry 1/2 ton status

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    Youn dont have to buy it from GM. Any parts store....about $7
     
  4. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Once again, guys: Do all Blazers have the limited-slip rearend?
     
  5. Cavalry

    Cavalry 1/2 ton status

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    I dont think so.....had one that I believed had the original axle and no posi. I know the diferance between LSD and locking.....why does my RPO sheet say "locking diff" if its a LSD
     
  6. Goose

    Goose 1/2 ton status

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    Nope, some are open diffs, some have the gov-lock, and some have limited slip. Limited slips need additive for the clutches in them, don't know if the gov-locks have clutches.

    Fencepost eater
     
  7. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    I understand how the limted slip differential works, and I believe I know the concept behind an open diff, but what about the gov-lock? And why would they sell a Blazer with an open diff?
     
  8. Cavalry

    Cavalry 1/2 ton status

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    Is there 2 different codes for LSD and a locking diff? Anyone know how to tell them apart?
     
  9. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    The GM code for limited slip is G80. I couldn't find a separate one for the locking diff.........maybe they are the same thing?
     
  10. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    G80 is the code for the gov-lock. I have no idea what the code is for the LSD. If ya don't beleive me pull the cover, if it looks like a cuckoo clock in there its a gov-lock (POS, just my experience [​IMG]). My 89 S-10 Blazer had the gov-lock and a G80 code in the glovebox. Did I mention how useless it was?[​IMG]

    Rene

    [​IMG]
     
  11. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Rene: My little book says the following-

    G80 AXLE POSITRACTION, LIMITED SLIP

    Man is this stuff confusing...........
     
  12. Blue85

    Blue85 Troll Premium Member

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    Does someone have a stock LSD that is not a Gov-Lock?

    The terms "locking differential", "posi-traction" and "limited slip" are often used interchangeably. I always figured that because of this, the "LSD" axles actually had the G80 Gov-Lock.

    "They tell me that you can make it to work without big tires. I'm still not convinced."
     
  13. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    The only thing I can think of is if G80 is the code for a traction aiding device, whatever the device was for that year. I know my S-10 Blazer was an 89 and it had the gov-lock and G80 in the glove box. Then again you never know for sure with the 'General'. When was the last year that GM offered the clutch type limited slip?
    When I bought my 88 GMC 2WD pickup in early 89 I was told it had the "locking" differential. Again, gov-lock and a G80 code.[​IMG]

    Rene

    [​IMG]
     
  14. 6.2Blazer

    6.2Blazer 1/2 ton status

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    To the best of my knowledge, the Gov-lock (option code G80) was the only limited slip type differential offered by GM in light duty trucks since at least the early 80's. GM called the Gov-lok a "locking differential" in the literature though it definitely qualifies as a limited slip. I think the confusion stems from people using the terms locker, posi, limited slip, locking diff, Gov-Lok, etc...all to describe the same thing. I don't know how many people I've heard say they have a "locker" in their new Z-71.......trust me, the Gov-Lock does not work anywhere close as good as something like a Detroit Locker, or even a good aftermarket posi/limited slip.

    Not all Blazers/Jimmys came with the Gov-Lock since this was an option.
     

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