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Want to change from 3.73 to 3.42 gears in a Z71

This is a discussion on Want to change from 3.73 to 3.42 gears in a Z71 within the Offroad forums, part of the General Discussion category; Hi all, I have a 1997 Silverado Z71 with push-button 4WD (electronic transfer case, option NP1), and it has the ...

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    Want to change from 3.73 to 3.42 gears in a Z71


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    Hi all, I have a 1997 Silverado Z71 with push-button 4WD (electronic transfer case, option NP1), and it has the 3.73 gear ratios. It also has the G80 rear diff. Without going into a long-winded explanation, let's just get down to business and say I want 3.42 gears instead. I probably have a little more car knowledge than the average joe schmoe, but I am by no means an expert.

    For the front differential, I know that in junkyards and on eBay I could find a 3.42 front axle diff. Would switching out the front diff be a pretty straightforward operation?

    For the rear G80 diff, would it just be a matter of switching the ring & pinion gears? Or would I have to get another G80 diff specifically for 3.42 gears?

    Thanks in advance for any help and advice!

    Cheers...

  2. #2
    Lifes tough, Get a helmet Public Nuisance's Avatar
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    Re: Want to change from 3.73 to 3.42 gears in a Z71

    For the rear the cheapest route would be to find an entire axle with the 3.42's and a G80. Then swap the entire thing and sell your old one. You could swap ring and pinion, but then you need to set them up, which you'll probably have to pay someone to do.

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    Mall Crawler loud93z71's Avatar
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    Re: Want to change from 3.73 to 3.42 gears in a Z71

    Can I ask why you would want to switch from 3.73's to 3.42's?

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    Shut your Butt JohnnyRingo's Avatar
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    Re: Want to change from 3.73 to 3.42 gears in a Z71

    i would swap diffs completely front and rear. theres to many 3.42 set ups floating around make it easy on yourself and you dont want the G80 anyway.
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    Mall Crawler loud93z71's Avatar
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    Re: Want to change from 3.73 to 3.42 gears in a Z71

    You could probably find some one on here that would be willing to swap with you.

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    Registered User SouthernTide's Avatar
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    Re: Want to change from 3.73 to 3.42 gears in a Z71

    exactly id swap front diffs with you and you could have my old 10 but looks like your a good bit aways away, i still need to match my 14sf gears.
    2006 Silverado 5.3 Z71

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    so cheap it's scary Stratosman's Avatar
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    Re: Want to change from 3.73 to 3.42 gears in a Z71

    Quote Originally Posted by loud93z71 View Post
    You could probably find some one on here that would be willing to swap with you.
    that's a good bet

    Used to own a FSC, now I just have my extremely old Buick.
    Have some perspective please. Thank you.

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    Re: Want to change from 3.73 to 3.42 gears in a Z71

    Thanks to everyone for all the replies.... I don't intend to do any towing or racing, it's basically my daily driver/company car, and being obsessive-compulsive I'd like to see if I can squeeze a little more gas mileage out of it as I do a lot of highway driving with it. (If they made 3.08 or 2.73 gears for 4wd silverados, I'd go with those, but they don't, so 3.42 is as low as I can go.) A friend has a '99 Tahoe with the 3.42 gears and I just seem to enjoy driving those gears more than my own. And I want to keep the G80 diff because of the harsh winters where I live.

    Like I said, I'm no expert, so I'd have to pay someone else to install either way. There is a guy here in Dayton whom I've gone to before for setting up rear ends, he has changed the ring & pinion gears in my Ford 9" rear Camaro a few times and he is excellent, all the local racers recommend him too. So I could hire him to do the ring & pinion gears and he's very reasonable pricewise.

    I would also be willing to consider trading out front and rear axles with someone who has the 4wd 3.42 G80 setup, just a matter of logistics, proximity, etc.

  9. #9
    98 Chevy Z-71 ksstang's Avatar
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    Re: Want to change from 3.73 to 3.42 gears in a Z71

    I wish you were ALOT closer and I'd trade you in a heartbeat. I absolutely HATE HATE HATE my 3.42's. My gas mileage sucks, towing sucks, etc with them.
    2004 Duramax LLY, EFILive with DSP5 Switch, Straight Piped, Eagle Alloy Wheels, Hankook ATM's

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    Registered User fuel583's Avatar
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    Re: Want to change from 3.73 to 3.42 gears in a Z71

    Yea man funny you should ask.... I was just thinking about how my truck has everything I want.... but wished it came with 3.73s, not the 3.42s...
    Last edited by fuel583; 08-02-2010 at 08:31 AM.
    '95 2500 / 5.7 / 6" Superlift / 2" BL / 16x10 589s / 36" TSLs / (sold)
    '06 Silverado Z71 / 5.3HO / AFE Intake / Corsa Sport / Blackbear Tune

 

 

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