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  1. #1

    Default G80 on front axle?

    I've just done an axle oil change on my 2002 Suburban 1500 4x4 LT. I have the build sheet for it, it states "Locking Rear Differential $252" however, when I drained the oil it was obvious the rear axle was a 'bog' standard rear axle, which made me think the dealer had "Ripped" the original owner for $252, but when I dropped the front skid pan, the front axle was I believe to be, according to the glove box info' a G80. My question is: Is this normal, to fit a locker/limited slip to the front axle? I've asked this question on another forum and the two replies I received more or less said I was mistaken, and that G80 are only fitted to the rear. Now I'm not completely "round the bend" but I've owned the motor for two years and not had any problems, never been stuck in snow, sand, mud etc, in fact in the snow, if I hit that "Auto 4wd" button when stationary and floor the loud pedal, there's no wheel spin and the Suburban takes off as if on a dry road. So: Is it normal to have a G80 on the front?
    Keep Rockin'
    Gus in the UK.
    Keep Rockin'
    Gus:great:

  2. #2

    Default

    The G80 Rear Axle acts like an open diff. You can spin one leg or the other and the axles are free so spin in opposite directions. The G80 "Gov Lock" as it's called is in fact an open differential for all practical purposes until one axle spins faster than the other. Then the axle locks and becomes a positraction. It still has clutches so it's a limited slip when locked.

    So to answer your question the G80 is in the rear. The front axles are all conventional open differentials.
    Jim

    2004 SILVERADO 2500HD LS
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    Other rides:

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  3. #3

    Default

    Quote Originally Posted by Jimmiee View Post
    The G80 Rear Axle acts like an open diff. You can spin one leg or the other and the axles are free so spin in opposite directions. The G80 "Gov Lock" as it's called is in fact an open differential for all practical purposes until one axle spins faster than the other. Then the axle locks and becomes a positraction. It still has clutches so it's a limited slip when locked.

    So to answer your question the G80 is in the rear. The front axles are all conventional open differentials.
    I looked in my 2002 Tahoe/Suburban owners’ manual to see what oils to use in the axles. For the Front Axle: It reads: SAE 80W-90 Axle oil (GM Part No 1052271). When I checked on the web what GM 1052271 oil is used for, this was the answer:

    If you have a locking differential (G80), you need to use SAE 80W-90 GL5 Gear Lubricant, GM P/N 1052271. Do not use limited slip additive.

    It would therefore appear that the 2002 4x4 Suburbans with a G80 limited/locking diff’ are all fitted to the front axles, why else does the manual instruction recommend the use of GM 1052271 in the front axle?

    The Recommended oil for the rear axle is SAE 75W-90 synthetic (GM Part 12378261)
    Which is for use in the normal standard axle.

    I would still like to know if this is standard practise and was wondering if there is a GM Chevy Suburban department I could contact at GM?

    I’d like to thank everybody for their comments. Cheers.
    Keep Rockin'
    Gus:great:

  4. #4

    Default

    GM never put anything but an open diff in the front (nobody aftermarket even makes a locker/limited slip for the 8.25 inch IFS that's in your 1500).

    The reason the part number for 80/90 gear lube mentions the additive for the G80 is because some years (like my '98) also recommended 80/90 for the rear axle (G80 or open).
    '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

  5. #5

    Default

    First off, let me thank you all for all your comments. You were all right the G80 locking diff’ is fitted to the rear. I’ll have to explain. When I performed the oil change I had jacked the whole vehicle off the ground, I then spun the rear passenger wheel and the drivers side wheel turned in the opposite direction, and therefore assumed the axle was a conventional one…which of course it is until one wheel spins 100 rpm faster than the other, you will have to excuse me for having a “senior moment”.

    My drive has quite a slope, so yesterday I placed a couple of 8x4 plywood boards on the drive and greased them up and placed them in front of the passenger side rear wheel, and as you would expect the wheel on the grease started to loose traction and the drivers rear cut in as smooth as silk, pulled off the drive no problem.

    I do hope this has not coursed an international incident or damaged Anglo-American relations.

    PS. Know of anything that removed burnt rubber & greaswe from block paving?
    Keep Rockin'
    Gus:great:

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