Where are you guys getting 315 gears?

Discussion in 'Transmission & Drivetrain' started by crcpdx, Jun 30, 2020.

  1. crcpdx

    crcpdx Well-Known Member

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    Changing from 3:55 to 3:15 gear. My understanding is I can't just change the gear but have to get a new dif. Where are you guys getting them? Hard to find online. I only saw on the Torsen site for $1,000 and they were out of stock
     
  2. K4fxd

    K4fxd Well-Known Member

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    Too bad you are in Ca. I have what you need. Shipping would be a biotch. Ky
     
  3. Dominant1

    Dominant1 Well-Known Member

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    Is a tune update needed for this mod of going from 3:55’s to 3:15’s. I have a 6r80 automatic?
     
  4. K4fxd

    K4fxd Well-Known Member

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    No tune needed on the 15's and up,. speedometer reads correctly.
     
  5. Dominant1

    Dominant1 Well-Known Member

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    I just bought a diff off ebay Yesterday with 3:15 gears for $230 shipped..its being delivered Friday. I have 3:55’s now which render my 1st gear useless with a 6r80. Should be perfect for my set up...
     
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    crcpdx

    crcpdx Well-Known Member

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    Trying to stay away from the OEM Trac loc dif. I would like to stay with a TQ bias dif
     
  7. Dominant1

    Dominant1 Well-Known Member

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    You wont find a irs torsen diff with 3:15 gears because ford never made them with 3:15 gears. You can build a torsen diff with a new 3:15 ring and pinion.
     
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    crcpdx

    crcpdx Well-Known Member

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    #8 crcpdx, Jul 1, 2020
    Last edited: Jul 1, 2020
    Torsen makes some, but they are $$$, waveloc might buy they are also over 1k. I've thinking about a 3:31. Just can't find a taller tire I like to fit my set up
     
  9. K4fxd

    K4fxd Well-Known Member

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    You will miss the 3rd and up gear acceleration. Personally I wouldn't go 3.15 unless FI or just highway cruising. I did get 28 MPG on the freeway at 80 MPH. Now I get 26 with the 3.55's
     
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    crcpdx

    crcpdx Well-Known Member

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    Lol, I get 8 mpg so not really worried about gas mileage. Also I have a 10r80
     
  11. Justgonna send it

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    Not trying to high jack Your post but I’m new to the stang game is there a noticeable difference between the 3.15 gearing and the 3.55 gears? Paired with v8 & 10sp.
     
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    crcpdx

    crcpdx Well-Known Member

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    If you're stock and plan to stay NA. IMO the 3:55 is the better gear. For guys running boost 3:15 is easier to control on the street and keeps you out of 7th gear at the track
     
  13. Justgonna send it

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  14. 101a

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    I would gladly swap my 18 3.15 aluminum pumpkin for any other ratio.
     
  15. Dominant1

    Dominant1 Well-Known Member

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    if your going with boost in the future You should keep them if not 3:55’s. I will sell you my 3:55’s once i get them swapped for my 3:15’s.
     
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