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NP241 Doubler

Discussion in 'The Garage' started by DPI, Apr 5, 2007.

  1. DPI

    DPI 1/2 ton status

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    Here's a couple pics of one of my latest projects. A D.D.Machine NP241 Doubler.

    This will be a nice addition to the Atlas II. Not that I need lower gears, but mainly to increase the front driveshaft length. However, with the doubler, I will have 2.72 or 4.3 to 1 low ranges... And I guess an 11.70 low range won't be a bad thing.

    The nice thing is the doubler kit weighs in at about 40 extra pounds.:D

    [​IMG]

    [​IMG]
     
  2. k204dr

    k204dr 1/2 ton status

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    sweetness, whats one of those run? guess I need to check out their website.
     
  3. muddermilitia

    muddermilitia ThatTrazerGuy GMOTM Winner

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    wow thats pretty cool, with 11.7:1 you could probably get out of your truck while its in drive and take pictures of it, then hop back in :D
     
  4. DPI

    DPI 1/2 ton status

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    He sells the kit for $399, plus the cost of the driver drop 241. I found a case for $90. So for under $500 I am building a doubler. I will also need my driveline lengths adjusted and I am building a new crossmember.

    He's over on Pirate. His ID is D.D.Machine and you can find more information in the vendor section.

    The hardest part of the kit will be welding the new end cap onto the case that was cut down. I picked me up a new to me Lincoln 250 amp TIG for that.:D
     
  5. muddermilitia

    muddermilitia ThatTrazerGuy GMOTM Winner

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    I heard that duffy wont be making the 241 kit much longer?
     
  6. DPI

    DPI 1/2 ton status

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    I guess it depends on demand.

    He also makes a 231 kit and says the internals are the same as the 241. Its just a smaller case.

    So if you can find a 231 from a S-10 with a 700R4, it should work too, maybe better with the smaller size...
     
  7. stallion85

    stallion85 1/2 ton status

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    Glad to see it put to use Daniel! I thought about putting it in the new Jeep, but I will probably use the 231 kit. Right now I need to just wheel and stop fixing things!!!lol
     
  8. Masiony

    Masiony 1/2 ton status

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    the s10 uses a 5 bolt round, and the full size uses a 6 bolt round adapter.
     
  9. mostwanted

    mostwanted 1/2 ton status

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    will an Atlas be the only t-case you could bolt up to this with the 241? I never heard of a 241 doubler, only the 203/205 doubler.
     
  10. 454k30

    454k30 1/2 ton status GMOTM Winner

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    the 241/205 doubler is kinda new news. I ran into that info when stallion85 and I were discussing something else. The welding is really the only difficult part of the swap it would seem but the end result is lighter that the 203/205 and has a deeper low range. Oh and the price is lower.
     
  11. mostwanted

    mostwanted 1/2 ton status

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    so technically, I could use my current tranny and swap out the 208 for a 241 and double that instead of replacing my output shaft to accept the 203, right?
     
  12. DPI

    DPI 1/2 ton status

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    According to Duffy, there are 6 bolt round pattern 231s, depending on the year. Tell you the truth, I've never seen one.
     
  13. DPI

    DPI 1/2 ton status

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    The 241 used as the "tripler" must be a drives drop. I called it the tripler because if you round up, its tripling that ratio:haha: ...

    But any transfer case with the 6 bolt round pattern will work as the primary transfercase. IE, 241, 208, 300, ect...
     
  14. Hossbaby50

    Hossbaby50 3/4 ton status

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    The best combo to run if you are going to run the 241 doubler is the 241/205 since the 205 is super strong. You can do a 241/241 or 208 doubler but you are applying alot more power to a case that may not be able to handle it for an extended period of time.

    Harley
     
  15. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    That is exactly what I have been wanting! I've got the cases in the garage. Got a link with the info?
     
  16. mostwanted

    mostwanted 1/2 ton status

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    why drivers drop?
     
  17. DPI

    DPI 1/2 ton status

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    Wasn't the 241 used in the Dodge 1 ton Diesels? That would be a lot of torque especially if it was behind a NV4500.
     
  18. DPI

    DPI 1/2 ton status

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  19. stallion85

    stallion85 1/2 ton status

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    Jeeps use a 6 bolt round 231 found behind xj's and others I am sure. My friend Trevor and I put his together and it is the same round pattern as one of my 241's. The internals are also the same.

    We swapped a 6 planetary gear set from a 241 into his 231. Usually you want to run a crawl box with the opposite drop as your rear case for front driveline clearnace.
     
  20. Masiony

    Masiony 1/2 ton status

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    not needed in most cases. since you cut off the front output anyways. the biggest case i know of is running a D300 behind them, you need to flip the first box opposite of the D300. in the case of a 241, you can just flip it. also, when using a 205, the rear shift fork needs some modifications to shift because it will run into the crawl box. duffy tells people to shift them from the rear, but you can also swap out the input to the long 32 spline chevy, and run a spacer (something like 2.25 inches) to gain the needed room to shift. this spacer would also give you a good chance to make the adapter use the 8 round pattern for your easy to find 205.
     

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