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Difference between thick or regular gears??

Discussion in 'The Garage' started by 85mudblazin, Jul 8, 2004.

  1. 85mudblazin

    85mudblazin 1/2 ton status

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    What the title says.
    14bff
     
  2. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Thick gears use a thicker ring gear so you can run lower (numerically higher) gear ratios with the 4.10 and down carrier.

    Otherwise you need to buy a 4.56 up carrier.
     
  3. 84gmcjimmy

    84gmcjimmy 1 ton status

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    Yeah, like tim said they just let you use lower gears in a higher gear carrier.
     
  4. HarryH3

    HarryH3 1 ton status Author

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    Uhh, one is thicker than the other? /forums/images/graemlins/eek.gif /forums/images/graemlins/wink.gif

    Take a look at the pinion gear on a 3.08 gear set. It has a lot of teeth and the gear end is pretty large in diameter. A pinion gear for the exact same axle, but for perhaps a 4.56 ratio will have fewer teeth and the gear end will be much smaller in diameter. As the pinion gear gets smaller, the ring gear has to move closer to the centerline of the pinion shaft in order to mate with the ring gear. On many axles there are 2 different carriers to accomodate the various gear ratio sets that are available. For example, on a 14-bolt full floater, one carrier was used for all gears of 4.10 and (numerically) lower (3.73, 3.42, etc), while another carrier was used for all gears of 4.56 and (numerically) higher (4.88 and 5.13). The difference between the two carriers is that the one used for 4.56-5.13's has the ring gear shifted closer to the pinion centerline. However, aftermarket companies sell "thick" 4.56-5.13 gears for that rear end that have the difference in the ring gear shift added to the backside of the ring gear. So when one of those gears is bolted to a diff that was designed for the 4.10 carrier, the ring gear and pinion will mesh properly. (While if you tried to use a thick 4.56 on a carrier that was designed for the 4.56 factory gears then the ring gear would never line up with the pinion gear.
     
  5. 84_Chevy_K10

    84_Chevy_K10 Banned

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    If you tried to use thick 4.56s in an axle with the 4.56 up carrier I doubt you could even install the carrier all the way as it'd be hitting the pinion.

    Interesting tech fact...Ford does not use carrier breaks. You should see how thick the 3.73s are in the 7.5" in the back of my DD.
     
  6. 85mudblazin

    85mudblazin 1/2 ton status

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    ok so the 14bff that I am buying has 3.73 gears does that mean I cant go lower than 4.10 gears?
     
  7. 84_Chevy_K10

    84_Chevy_K10 Banned

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    You can put whatever gears you want in it up to 5.13s by using a thick gearset for 4.56, 4.88, or 5.13.
     
  8. HarryH3

    HarryH3 1 ton status Author

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    [ QUOTE ]
    ok so the 14bff that I am buying has 3.73 gears does that mean I cant go lower than 4.10 gears?

    [/ QUOTE ]
    Sure you can go lower, but you'll have to buy thick gears to fit that particular carrier if you want 4.56's, 4.88's or 5.13's. /forums/images/graemlins/thumb.gif
     
  9. 84_Chevy_K10

    84_Chevy_K10 Banned

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    /forums/images/graemlins/thinking.gif /forums/images/graemlins/whistling.gif
     
  10. HarryH3

    HarryH3 1 ton status Author

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    For a good article on carrier breaks and why they exsist click here: http://www.randysringandpinion.com/tech/tech.asp and then click on the "Do I Really Need to Buy Another Carrier*" link on the page that comes up. /forums/images/graemlins/thumb.gif
     

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