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  1. #1

    Default 89 burb: does 4x4 = posi rear end?

    Hi I have a 1989 suburban 2500 4x4 with manual lock out front hubs. My question is, when I shift into 4x4 does that lock the front and rear axles into posi-traction?

  2. #2

    Default

    Shifting into 4wd only locks the transfer case. The differentials operate completely independently. I doubt there's any kind of traction aid in the front diff, unless you've put it there, because OEM's don't like to put traction aids up front at the factory. Rear may have a traction aid or may not. G80 is the usual RPO code to look for, but I don't know if that will refer to the Eaton Gov-Lock or a clutch type LSD in your year.
    '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

  3. #3

    Default

    Thanks MrShorty

    I noticed while crawling under the truck that there is a cable that goes to a lever sticking off of the rear pumpkin. I thought maybe that was linked to a diff lock or something that activated when in four-wheel-drive. From your response it sounds like it is possible the rear has a locking device, but for sure the front would have an open differential?

    I always thought that the rason they didn't want you to drive on dry pavement in 4x4 is becuase all the differentials are locked?

    So without a traction device up front, in most slippery situation (like mud) you really end up with 3 wheel drive if one of the front wheels starts spinning since there is an open differential up front?

    Also where would I find the RPO code? Is that on the rear axle?

    thanks for the insight!!

  4. #4

    Default

    When you open up the glovebox, there should be a fairly large sticker there with a whole ton of incomprehensible numbers and letters. Those are your RPO codes. If you decode those RPO codes, you will find out pretty much every single option, nuance, and otherwise about the truck when it left the factory, right down to the original colors.
    Christopher

    1991 Chevy Suburban 1/2 ton 2WD w/ chevy SBC 350-3/4 ton drivetrain upgrade w/4.10 gears 200K miles
    2005 Saturn ION-2 Stock 277K miles
    1982 Bronco, 1993 Bronco (sold), 1971 M35A2 Deuce and a Half



    There are 10 kinds of people, those who understand binary, and those who dont...

    Remember kids, the only difference between screwing around and science is writing it down- Adam Savage

  5. #5

    Default

    Thanks Crawdaddy! Now I know what I'm going to do as soon as I get home. Find out what treasures are lurking in that $500 hunk of smoking metal! (hopefully the smoke will go away when I get the new engine in!)

  6. #6

    Default

    OK, I'm learning about my truck. I checked the RPO codes and have GQ1, GU6, G80. Does that mean I have open diff in front, 3:42 gears, Posi in the rear?

    '93, 1500, Burb, 5.7, 4x4

    Found a link to this website on another posting

    http://www.rpocodes.com/GM-RPO-codes...GthroughM.html

    Researched my RPO and this it what I found

    GQ1- Open Diff
    GU6- 3:42 gears
    G80- posi traction/locking diff
    Z82- Trailering equip'd
    M30- 4L60E, 4-Speed Auto
    L05- v-8, 5.7, TBI
    Last edited by AdvSwede; 01-13-2013 at 04:29 PM. Reason: additional information

  7. #7

    Default

    Try this: http://www.rpocodes.com/


    Looks like you were editing while I was posting. I like that site, they seem to keep it updated. Good luck
    Last edited by RayVoy; 01-13-2013 at 05:45 PM.
    Ray

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

  8. #8

    Default

    Quote Originally Posted by AdvSwede View Post
    OK, I'm learning about my truck. I checked the RPO codes and have GQ1, GU6, G80. Does that mean I have open diff in front, 3:42 gears, Posi in the rear?

    '93, 1500, Burb, 5.7, 4x4

    Found a link to this website on another posting

    http://www.rpocodes.com/GM-RPO-codes...GthroughM.html

    Researched my RPO and this it what I found

    GQ1- Open Diff
    GU6- 3:42 gears
    G80- posi traction/locking diff
    Z82- Trailering equip'd
    M30- 4L60E, 4-Speed Auto
    L05- v-8, 5.7, TBI
    Yes it does, providing it hasnt been swapped out over the years.

  9. #9

    Default

    Thanks RayVoy

    - - - Updated - - -

    Tim,

    I guess I can see what happens in the snow when I get the Master Cylinder fixed. Thanks

  10. #10

    Default

    Quote Originally Posted by Big6ft6 View Post
    Thanks MrShorty

    I noticed while crawling under the truck that there is a cable that goes to a lever sticking off of the rear pumpkin.


    I believe what you saw was the brake bias lever. It adjusts the brake pressure by sensing how much the suspension compresses from a heavy load.

    97 Chevrolet Suburban K1500 5.7L
    78 GMC High Sierra K1500
    Fat, drunk, and stupid is no way to go thru life.

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