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Gear question. (I know, there are alot, but this is different)

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Cold_Spider, May 7, 2003.

  1. Cold_Spider

    Cold_Spider Newbie

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    Ok, it is about axle gearing and I know that alot of sites have lists of what to choose. But all for the USA.

    Se here goes. I have a 350 engine th700r4 tranny np208 case. I run 35inch tires. The max speed in europe is 80MPH. So I'll be cruzing at 60 to 85 MPH on the highway. So that will be in overdrive. When pulling a trailer in drive I'll be at 50MPH. Still I'll be going offroad as well.

    To sum it up:
    OD = 85MPH tops
    D = 50MPH tops pulling a trailer.
    Tires are 35"

    I have 4.11 in a 12bolt now and 3.08 in the front. I want to know if I can best put 4.56 or something in both or put 4.11 in the fron as well.

    Thanks in advance.
     
  2. outlaw612

    outlaw612 1/2 ton status

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    I have 4.56's with my 36" tires and I run around 80 on the highway in OD with no problems. I would reccomend the 4.56's.
     
  3. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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  4. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    go with the 4:56's /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  5. Flexy K20

    Flexy K20 1/2 ton status

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    Well, first of all you cannot have different gears, if you have 4.10's in the front you need the in the rear...etc. If you have missed matched gears, in 4 wheel drive it will cause problems because the front and rear tries will spin at different speeds. Also so people can help you better fill out your profile. Later
    -fLeXy K20
     
  6. gravdigr

    gravdigr 1/2 ton status

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    "I have 4.11 in a 12bolt now and 3.08 in the front."

    I bet running in 4wd is a treat with this. Unless you are running smaller tires in the front your front wheels are spinning faster than the back ones in 4wd. This cannot be, maybe in a np203 unlocked, but eventually that transfer case would crap out.
     
  7. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Even if he was running smaller tires in the front, it wouldn't matter. He'd have to have 20" tires in front and 35s in back to make it work right. He obviously knows he needs matched gears, that's why he's asking questions.

    I'd go with 4.56 if you plan on keeping the OD automatic. I had a 700R4, 35s, and 4.10s and hated it. 4.56 is MUCH better. If you plan on going with taller tires EVER, go with 4.88s. I wouldn't even consider anything numerically lower than 4.56.
     
  8. Cold_Spider

    Cold_Spider Newbie

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    Well I know that having different gears is a problem. But I got the 12b with 4.11 and took a 10b out with 3.08 about 2 years ago. Just did now go 4x4. Now I am looking to do so, and reading all of this, I think I convert the front and the rear to 4.56. I'd never go over 35's I think. Some legal issues here. But if I ever, will 4.56 then be a problem with 36? 38? bigger?

    Thanks all of you. I know will fill in my profile!

    P.S. Is it me or are 4.88 gears for the 10b front and 12b rear rare?
     
  9. Troopie's Tonka

    Troopie's Tonka 1/2 ton status

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    Well, I'm no gear guru or anything, but i'm thinking that 4.88's in a 12 bolt will break before you even put that nifty shifter into 4WD. I have 4.56's in my 12B with 36" Swampers. I had fun for a while, but I don't wheel as hard as most of the guys on here, and finally broke it. That is why I am currently looking into a 1 ton for my rearend. Put some 38's on 12 bolts with 4.56, you'll break something the second you try to out run one of those ricer teenage guys. Good luck /forums/images/graemlins/k5.gif
     

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