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What gear's ? 4:10's or 4:56's

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by jtpepper, Oct 21, 2002.

  1. jtpepper

    jtpepper Registered Member

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    What gear\'s ? 4:10\'s or 4:56\'s

    I'm trying to decide what gear's to install in my Jimmy.I'm currently running 33's on it,but I plan on going up to 36's.Now the kicker is that I'm also building a 454 for it.I have a 700r4 tranny in it that I plan on keeping.I also pull a 20ft travel trailer with it.What would be the best all around gear for this set-up and what would my rpm's be at 65mph?Thanx guy's and GOD Bless,jtpepper
     
  2. zakk

    zakk 1/2 ton status

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    does no one lurk anymore? this was covered not 12 hours ago /forums/images/graemlins/rolleyes.gif
     
  3. K5DRAGER

    K5DRAGER 1/2 ton status

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    I think what he's trying to say is try the search button. This topic has been covered many times and you should find alot of info.
     
  4. zakk

    zakk 1/2 ton status

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    yes, thank you, Brent. i just couldn't bring myself to type the "s" word again /forums/images/graemlins/grin.gif
     
  5. Z3PR

    Z3PR Banned

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    I'd go 4:88 gears !!!!
     
  6. K5DRAGER

    K5DRAGER 1/2 ton status

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    No problem Zakk!
     
  7. BLUESMAN

    BLUESMAN 1/2 ton status

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    Damn sure hope you got them ultra strong 10 bolt diffs to run with that 454/TH700 combo!!Go with the 4.88's...the thinner the better! /forums/images/graemlins/blush.gif
     
  8. jtpepper

    jtpepper Registered Member

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    All I asked was a simple question..........
     
  9. rogerwilco71

    rogerwilco71 1/2 ton status

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    Hmm, big block and 36's with a trailer...I'd go with the 4.56's
     
  10. jtpepper

    jtpepper Registered Member

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    Thanx Roger.Appreciate the nice reply.jtpepper
     
  11. Hossbaby50

    Hossbaby50 3/4 ton status

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    I have to agree. I would go with 4.56's. I have 4.56's with 32's currently (350/700R-4) and I like the combo. The RPM for cruising on the highway is my only downfall. But I don't plan on keeping the 32's I am on my way to 35-37" tires where cruise RPM will be better. I will also agree on the whole 10 bolt 4.56 gear thing too. If you plan on doing any decent fourwheeling your axles are going to sound like an original episode of Batman. Bang, Crash, Pop, etc. The front 10 bolt might hold for awhile, but the rear is toast. I toasted a 10 bolt with a stock 350, 3.73 gears, and 32" tires. All I can say is beef your drivetrain like you plan on beefing your motor. You are going to need to build the 700R-4 well to handle a healthy big block, the rear axle will most likely need to go to a semi floating 14 bolt (minimum).
     
  12. BLUESMAN

    BLUESMAN 1/2 ton status

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    Trying to tell you that the TH700 trans will not hold up to that 454 torque,unless you are planning on spending a large chuck of cash on upgrading it.The 10 bolts will explode with that kind of torque and size of tires,and you are planning on towing??I would upgrade to an TH400 trans and 3/4 ton diffs with 4.10's.You can go a little smaller on the gears with a big block motor.Unless this is just for a "pretty" truck,you'd be better off building it right the first time.I would'nt want you stranded in the middle of nowhere with exploded diffs and trans.Mike
     
  13. Z3PR

    Z3PR Banned

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    Didn't realise we was talking 10 bolters. Go out and find atleast 3/4 ton axles, you should be able to find a set with the gears you want for less then regearing 10 bolters.
     
  14. imiceman44

    imiceman44 1 ton status

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    From what I can understand in your post I think you want an all around truck that will tow your trailer to a playground where you can flex your muscles.
    If you don't plan on beating the hell out of it, you should be fine with either gears but I guess 4.56 will be easier on the 700r4.
    I have a 12 bolt with 35" tires and I am not too carefull but also not careless and so far in 2 years I haven't broken down yet /forums/images/graemlins/smile.gif.
    So it's all up to your right foot.
     
  15. jtpepper

    jtpepper Registered Member

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    I should of clarified what I do with my Jimmy.It is strictly a play toy,huntin' buggy,beach wagon.I doubt I'll ever be rock climbing or mud boggin'.I pull my trailer to the beach,to the huntin' lease and back home.I only engage the front when the need arises.So I guess this is one of those purty trucks.I feel I need a little more towing power,especially when I go to bigger tires.Thanx and GOD bless,jtpepper
     
  16. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    Towing with 36s....? I'll look for a gear calc but you probably already know that you can not run OD towing.

    I have 4.10s on true 35" tires with a 350 - D is great for freeway speeds. OD works at about 75mph or higher. Wish I would have gone 4.56s even tho I couldn't tow as fast (55mph speed limit anyway...).

    Do you wheel the beast? If you don't you can get away with 4.10 - the BB will push that around fine and it might save you some MPG on the freeway.
     
  17. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    Another thing - put a 14FF in the rear. You don't want a fatigued axle popping out under heavy acceleration on a freeway on-ramp.

    I would say that upgrade is mandatory for safety in your situation.


    Then there is the tranny..... /forums/images/graemlins/blush.gif
     
  18. JK5

    JK5 1/2 ton status GMOTM Winner

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    I went with 4.10's .....I wish I went with 4.56's.....with 35"s.......My truck flies on the freeway.......but I think 4.56s would be better for crawling.
     
  19. jtpepper

    jtpepper Registered Member

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    Thanx for the replies.I'm finding out that it's one thing after another but I truly enjoy piddlin' with this ol' Jimmy.I found a 14ff today at a junkyard that is bad,don't know what,for $200.Around here a good one is $500-$750.I might take a chance and get it.Again thanx.GOD bless,jtpepper
     
  20. bablazer73

    bablazer73 1/2 ton status

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    Re: What gear\'s ? 4:10\'s or 4:56\'s

    I sort of agree with every body else. 4.56 gears, loose the 700r4, won't last with a big block anyways. hell, the don't last with stock 305's!! and put 3/4 ton axels. the 10 bolts will pop. 36's may be to tall to tow well with.
     

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