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38's with what gears?

Discussion in 'The Garage' started by Shagnaz, Nov 15, 2002.

  1. Shagnaz

    Shagnaz 1/2 ton status

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    38\'s with what gears?

    I have a stock 350 with Dana 60 and 14 bolt FF. I am running 38's. I know the 4.10 is not enough and the front has 4.56. I am about to change the gearing and want to know - Should I go with 4.56's or 4.88 with a 700R4?

    Thanks for the time!
     
  2. BLUESMAN

    BLUESMAN 1/2 ton status

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    Re: 38\'s with what gears?

    I run 4.10 with my 38's and it's great!!When I had the TH350 it was sluggest,but OK.With the manual it's very good.Of course my K/5 is on a serious diet,no top,tailgate,half doors,stripped interior,no A/C,heater, and a liter '81 front clip.I'd go with 4.88's with that TH700 overdrive trans.That or swap in a SM465 Manual and install rear 4.56 gears.....bombproof!!I just don't trust them 700 trannys!!Mike
     
  3. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    Re: 38\'s with what gears?

    I know 38s on 4.56 works pretty good... especially with a doubler /forums/images/graemlins/wink.gif
     
  4. BorregoK5

    BorregoK5 1/2 ton status

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    Re: 38\'s with what gears?

    I run 38's and 4.56 gearing with 1 ton axles on a th350 and it would be perfect with a doubler. I think I'd like 4.88 but with a 700r4 and overdrive, I would assume that would be your minimum.
     
  5. zakk

    zakk 1/2 ton status

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    Re: 38\'s with what gears?

    5.13's if you still might go to bigger tires,

    if 38's are the end of the road, 4.56 is a nice medium but 4.88 would be my pick
     
  6. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    Re: 38\'s with what gears?

    here are your options in my opinion
    1 plan on biger tires? do it right the first time and go 5:13's rpm will be a little high on the freeway but with the 700r4 AND A ADDITINAL TRANNY COOLER you will be fine
    2if you have the money and you plan on staying with 38's or 39-39.5's go with the 4:88's
    3 if you dont have the money only change the one axle to 4:56's since you have one with 4:56's anyway but you will want 4:88's gauranteed even with just the 38's
     
  7. ChevyCaGal

    ChevyCaGal 3/4 ton status

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    Re: 38\'s with what gears?

    I have a set of 38.5's I am going to be putting on, also a new set of one ton axles.... my gearing will be 4.56. I also have a 700R4 tranny. I will add a tranny cooler as well.... but that's the combo I plan to do. /forums/images/graemlins/cool.gif
     
  8. Shagnaz

    Shagnaz 1/2 ton status

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    Re: 38\'s with what gears?

    I wanted to go with the 5.13 set up, but was told that it would create alot of heat. Exspecially towing my car trailer. That is why I was thinking of the 4.88's, but then I thought of this...how much difference is there b/w 4.88's and 4.56?
     
  9. Shagnaz

    Shagnaz 1/2 ton status

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    Re: 38\'s with what gears?

    How or why are you going with this set of gears?

    /forums/images/graemlins/k5.gif /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif
     
  10. ChevyCaGal

    ChevyCaGal 3/4 ton status

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    Re: 38\'s with what gears?

    Well the axles I bought have 4.56's and then I got a good deal on the 38.5's... a friend of mine said they'd work. I trust him. He's into Jeeps but be he builds them frame and all and does amazing fab work. If he were into K5's he'd be my best friend! /forums/images/graemlins/grin.gif But really he's been wheeling for like 30 plus years. His knowledge of this stuff is amazing. So if he says I can use this set up and it will work I trust him. He did say it won't have the power off road like if I went with 5.13 or 4.88 but I'm going to be using this a lot just to drive around town as well... I know gas mileage is a joke, but I still don't want to totally kill it for me altogether which is another reason...
     
  11. Shagnaz

    Shagnaz 1/2 ton status

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    Re: 38\'s with what gears?

    Is what I said about the gears heating up too much true with the 5.13's? I don't know.

    Will moving from 4.56 to 4.88 make that big of a difference? The difference is only 8%.

    If anyone did this, please let me know.
     
  12. 6.2Blazer

    6.2Blazer 1/2 ton status

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    Re: 38\'s with what gears?

    My first suggestion would be to run 5.13's since you have the 700r4. While cruising in overdrive this would give you an effective gear ratio of around 3.60 (5.13 x 0.70), with 38" tires I don't think you would have any worries about too high of engine RPM.

    However, you also mentioned something about pulling a car hauler. I am assuming you do not use OD when towing so engine rpm might be a little on the high side when towing in drive with the 5.13's, again assuming you tow for longer distances on the freeway.

    Concerning heat build-up with 5.13 gears, I don't really know of any reason they would generate more heat than 4.88's???

    For differenes in gears, in my opinion and personal experience it is pretty hard to tell the difference between ratios that are just one step apart, for example 4.10 vs. 4.56, 4.56 vs. 4.88.
     
  13. Blazinaire

    Blazinaire 1/2 ton status

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    Re: 38\'s with what gears?

    My $.02: I run a 700R4 with 35''s and 4.56's. I drove 1000 miles on the highway without even using OD (not by choice, but I did it), so I think that with my OD I could get away with 4.88's and 35''s but I don't feel the need for it. Now with 38.5''s I would go with 4.88's minimum and possibly even 5.13's it really depends how low you need your gears for crawling vs. how much you drive on the highway. If it was my truck and I was gonna stick with 38.5''s I would definately go with 4.88's. BTW I get around 18mpg
     
  14. m j

    m j 1/2 ton status

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    Re: 38\'s with what gears?

    4.10s and a doubler would be my choice
    the difference between 4.10 and 4.56 or 4.56 and 4.88 is negligble

    gear the difs for the highway and IMO 35" tires.
    Trust me, you will one day get sick of the crappy tires that are available in over 35" sizes.
    35"s are so cheap compared to larger tires and they are available from nearly every manufacturer
    use the doubler for deep gearing offroad.
     
  15. florida4x4

    florida4x4 1/2 ton status

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  16. Shagnaz

    Shagnaz 1/2 ton status

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    Re: 38\'s with what gears?

    I am going to try to use the 4.56's for now, since that is what is in my Dana 60 already. I really want 5.13's though, but will have to wait till summer.

    THANKS TO ALL WHO GAVE THEIR TIME TO HELP
    /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
    /forums/images/graemlins/k5.gif /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif
     
  17. 86K5TrailBlazer

    86K5TrailBlazer 1/2 ton status

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    Re: 38\'s with what gears?

    you can talk yourself out of it but 5.13 is what your gonna want - need
     
  18. Shagnaz

    Shagnaz 1/2 ton status

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    Re: 38\'s with what gears?

    You're right. I am going to try to get the 5.13's, but worst comes to worst, I am going with 4.56's

    Anyone needing a set of Dana 60 4.56 gears or 14 bolt 4.10's? hahahaha
    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/usaflag.gif /forums/images/graemlins/usaflag.gif /forums/images/graemlins/usaflag.gif /forums/images/graemlins/usaflag.gif /forums/images/graemlins/usaflag.gif
     

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