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  1. #1

    Default 05 Sierra SLT question on gearing.

    I was wondering how to check what gears I have, and depending on what I find, what is a good rear end to have. Reason I asked is this truck runs at 1800 rpm or so running down the highway at 70, wereas the silverado i used to have ran just a hair over 2000.

    wondering if I have 3.43 vs 3.73

    thanks in advance.

    Alex


    2011 GMC Sierra SLE 5.3 Z71 4X4 Stealth Gray Metallic / 2004 Chevy Impala LS 3.8 Cappuccino

    Tow mirrors - Diablew Tuned - Flowmaster Regular 40 - Ready Lift 2.5' lift - BFG LT A/T K/Os - Carr Light Wing - TruckLite LED lights - Optima Red Top - 50% Front Window Tint - Line-X bedliner - Airaid MIT - Tekonsha P2 - ARS Billet Grill - Fia custom fit seat covers

  2. #2

    Default

    Quote Originally Posted by Sierraowner5.3 View Post
    I was wondering how to check what gears I have, and depending on what I find, what is a good rear end to have. Reason I asked is this truck runs at 1800 rpm or so running down the highway at 70, wereas the silverado i used to have ran just a hair over 2000.

    wondering if I have 3.43 vs 3.73

    thanks in advance.

    Alex
    The way to find out What Gears you have......In your Glove Box is a White Sticker and on it....you will see the Trucks Vin # and a Series of Letters and Number's,those are RPO Code's....Which stands for Regular Production Options....In Short it what your Truck came with from the Factory.

    To find out what Gears you have you will be looking for one of the following,

    GU5.......3.23
    GU6.......3.42
    GT4.......3.73
    GT5.......4.10



    MIKE


    99"SILVERADO
    5.3 l 3.73 l G80
    BLACK BEAR CUSTOM TUNE
    SNUGTOP l COLORMATCH l KATZKIN










  3. #3

    Default

    You may have 3.23's.

  4. #4

    Default

    just went and looked, got the 3.42s. if i were to change em, what would be better, 3.73 or 3.90s?

    Alex

  5. #5
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    Default

    depends what you are planning on doing. 3.73 are the prefered gear in my book. they offer the best for highway, and towing at the same time. You go any higher and you are drinking fuel any lower and you dont have any power when you need it towing.
    now that is running the stock truck or close to it.
    Mike

    Currently

    1997 Chevy S-10 Blazer 4X4 with 330K miles and counting (Hunting rig).

    2009 Saturn Aura XE (wifes car)

    2011 F-150 Crew 4X4

    "Hold it to the floor till you see God.... Then Brake!!!!"

  6. #6

    Default

    X2, I'd go with the 3.73's.

  7. #7

    Default

    well, what would swapping to 3.73s cost? im planning on doing a front end level, but not jacking it up any, a size larger tires may find there way on there at some point, but im not planning on lifting or putting 35s under it. gas costs to damn much.


    Alex

  8. #8

    Default

    since you would need to do front and rear gears with a 4x4 you are looking around $1200-1500 (maybe a little higher depending on place brand etc). I would also recommend the 3.73 with what you are suggesting as upgrades and driving.
    David
    2004 Silverado 2500 Crew Cab 4x4, AMSOIL EA air filter, Granatelli MAF sensor, Throttle body spacer, Magnaflow exhaust (true dual to 2 in 1 out muffler), 6" ProComp lift (add a leaf and 5" superlift rear block), Bilstein shocks, 35's (Cooper Disoverer ST) and 4.10 gears, Rhino Liner, EGRUSA fender Flares and widow visors, extended stainless steel brake lines, firestone airbags w/onboard air compressor, Pioneer Avic X940BT navigation, Accel backup camera.
    http://www.gmtruckclub.com/forum/sho...Silverado-2500
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  9. #9
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    IF you arent planning anything drastic, then stick with the 3.42s since the cost wont pay for itself. especially if you use the truck more as a commuter than anything else.

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