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  1. #1

    Default factory rear locking-differential

    how do i know if i have this on my 99' tahoe 4x4? i know some came with it, some came without. thanks.

  2. #2


    In your glove box you will have a sticker put on by the factory with a bunch of number and letter codes. The code you are looking for is G80. If you see this then you have the locker.
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    ...and every one of em has issues

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  3. #3


    thank you kindly sir.

  4. #4
    Master Mechanic TahoeFever's Avatar
    Join Date
    Sep 2007
    Now IN Auburn AL :)


    those numbers on the glove box are the options that the truck is able to take doesnt mean that it has it on board....? if that was the case i'm missing alot of goodies that my truck had when it left the factory
    04 Tahoe LT 5.3L stock MSD 8.5mm Wires
    Gigbson Duels Straight Exhaust, Parrot 3100 Bluetooth
    K&N 77 Series CAI, Sirius Radio
    De-badged, Valet Dei remote start
    5000k HID
    Federal 100watt air horn

  5. #5


    The RPO codes are supposed to indicate what options that individual truck was outfitted with from the factory. I don't know what to say if you seem to missing options.
    '98 K1500 Suburban LS 5.7 L 4L60E NV246 ARB
    '92 Ford Explorer XLT 4x4 4.0 L A4LD BW13-54 Trac-loc rear
    "My toys were the greasy cogs and springs and pistons that lay around all over the place, and these, I can promise you, were far more fun to play with than most of the plastic rubbish children are given nowadays." Danny in Roald Dahl's Danny The Champion of the World

  6. #6


    so if i see G80, i have limited-slip or what?

  7. #7


    A '99 with a G80 will have the Eaton Gov-Lock rear locking differential. Under normal driving conditions, it behaves like a normal open differential. When vehicle speeds are below ~20 mph and one wheel spins ~100 RPM faster than the other, there's a mechanism in the differential that locks the differential to send power to both wheels. It's a true locker, only it's kind of opposite of other "automatic" lockers. Other lockers are normally locked, but have a mechanism to allow for differentiation when cornering. The G80, on the other hand, is normally open, but locks up under certain circumstances.

    I know I've seen it before, but I can't remember where it's at, but there's a short video somewhere on the internet that shows how it works. Put "Eaton Gov-lock" or G80 into your favorite search engine and you'll find lots of hits.

    It also seems to have a bad reputation on the net, especially the 10 bolt version (which is what should be in your Tahoe). Some attribute it to "abuse". Where the mechanism "locks" it together after it's started slipping, it can be pretty "harsh" under the right conditions, which probably contributes to it breaking, especially in the smaller 10 bolt rear.
    Last edited by MrShorty; 12-29-2007 at 10:09 PM.

  8. #8


    thanks mrshorty!

  9. #9


    whould the code be the same for a 2000 gmc sonoma.

  10. #10


    Should be the same

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