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14b FF gear ratio

Discussion in 'The Garage' started by ramses, Mar 9, 2005.

  1. ramses

    ramses 1/2 ton status

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    A friend called me and asked how to find the ratio in his 14 bolt rear end and I recalled that I devided the two numbers that were on the ring gear to get my ratio of 4.10 in my 14 bolt. The two numbers he gave me were 45 and 14. I cant remember my numbers to compare them, do those numbers sound right for the amount of ring and pinion teeth? Dividing the two numbers comes to something like 3.2....., which didnt make sense to me because I thought it was supposed to come out as a 3 digit number first of all, and second of all, I didnt think a 14 bolt rear end came with any higher gears than 3.73. The gears arent as low as mine, so I assumed they were 3.73. Were there ever any other ratio's in 14 bolt FF rear ends? Or are those numbers he gave me wrong and its probly just 3.73? I think he said he counted the teeth on the ring gear and came out with 45 so I assumed that at least that number was right. Maybe the pinion teeth number was wrong?
     
  2. dremu

    dremu Officious Thread Derailer Premium Member

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    From Billavista's 14BFF bible...

    http://www.pirate4x4.com/tech/billavista/14b_bible/index.html

    There are 41 or 39 teeth on the ring, and 8, 9, 10 or 11 on the pinion.

    -- A
     
  3. sweetk30

    sweetk30 professional hooker Premium Member

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    you might have some date codes or casting # mixed in there just count the teeth and divide the small in to the big and get like 4.10 or 4.56 or 3.73
     
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    There was a 3.21:1 ratio offered, although it may have been a 2WD thing. I know a member here, U2Slow, swapped in 3.21's into his 6.2 burb.

    Best is to get the numbers directly off the edge of the ring gear, rather than trying to count teeth.

    Rene
     
  5. dcubb

    dcubb 1/2 ton status

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    Here's a very simple method to determine axle ratios with out pulling the diff cover.

    If the axle has a open diff,

    1...jack up one wheel
    2...put mark on pinion and housing for reference
    3...have a buddy turn the wheel exactly TWO turns
    4...count number of turns of pinion (i.e. aprox 3 1/8=3.08, little under
    3 1/2=3.42, 3 3/4=3.73, 4 1/8=4.10 and so.

    If running limited slip, locked etc, jack up both wheels and just make sure BOTH wheels are turning together and turn only ONE turn while counting pinion revs.
     
  6. u2slow

    u2slow 1/2 ton status

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    Thanks Rene,

    I put a complete 14ff w/3.21 in my Burb.

    3.21 and 3.42 are usually found in big-block trucks.
     
  7. ramses

    ramses 1/2 ton status

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    So there was a 3.21 ratio offered. I didnt think gears that high were put in 14 bolts. The truck it came out of was a 3/4 ton 4wd and I think it was a 79 model and had a 350 in it. I have heard of that method of jacking up one wheel and finding the ratio, but I assumed it didnt work if larger than stock tires were on the truck. Or am I wrong? Ive been thinking that id like to have a limited slip in my 14 bolt, but I havent seen one anywhere. Is there one available from anywhere, and if so, what is involved in the installation of it?
     

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