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New transfer case mod possibly?

Discussion in 'The Garage' started by Thumper, Aug 22, 2004.

  1. Thumper

    Thumper 1/2 ton status

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    I was just out at my buddys place helping him with his CJ-7. He is in the process of swapping in a Vortec V-6 fuellie from an S-10 into his Heep. He has found a SM420 tranny and has it hooked to his D300 T-case. We were talking about crawl ratios etc, and he figures that he is going to be around 96:1 with his setup. We figured mine out to be 53.1:1 with my 465, 205, and 4:10s. He says the Dana300 case is a gear drive case with a 2.62:1 low range. If I swapped one of those behind my 465, it would put me up to 70.3:1. It cost him around $500.00 for the adapter from the GM tranny to the AMC case. I am seriously contemplatin this... is it worth $500.00 for the adapter, and $150.00 for a D300 case to gain nearly 20:1 worth of crawl ratio?
    Has anyone already done this swap?

    Mike
     
  2. Thumper

    Thumper 1/2 ton status

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    No thoughts or opinions?

    Mike
     
  3. CyberSniper

    CyberSniper 1/2 ton status Premium Member

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    I'm not sure how strong a Dana 300 is and it seems that the cost is approaching doubler country. I know the Heep guys swear by them.
     
  4. smprider112

    smprider112 1/2 ton status

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    ya for that price, either get a 208 or 241 for a poor man doubler...or get a 203 range box and ORD's doubler kit for some real crawl ratio!! bout 105:1 /forums/images/graemlins/peace.gif /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  5. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    [ QUOTE ]
    No thoughts or opinions?

    Mike

    [/ QUOTE ]

    In a full size truck with a big block and 38's you'd nuke that D300 in no time.

    Rene
     
  6. Thumper

    Thumper 1/2 ton status

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    [ QUOTE ]
    for that price, either get a 208 or 241 for a poor man doubler

    [/ QUOTE ]
    Are these both not chain drive units? The D300 is a gear drive same as a 205.

    And as far as a doubler... the price is about half one. I can get this setup for around 650.00 CDN, where as ORD doubler is around 1200.00 USD plus finding a range box, and a new 465/ 205 setup with the right spline count since no-one finds it necessary to make a 10 spline kit anymore. So... at 650.00 vs 2000.00 the price doesnt compare. Way less than half. As for strength... they ran these cases behind AMC 360s. The info I have is that they are very strong. Lots of Jeep guys run them behind 360s or 350s with NV4500s. Hmm... worth doing some research tho. I needed some input. /forums/images/graemlins/thumb.gif

    Mike
     
  7. smprider112

    smprider112 1/2 ton status

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    they are chain...but prolly about as strong as a 300 is...regardless its gear driven, doesnt mean its any where near as strong as a 205...I'd look into a 208 or 241 still /forums/images/graemlins/thumb.gif
     
  8. CyberSniper

    CyberSniper 1/2 ton status Premium Member

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    I'm pretty sure the weak part on a 208 and 241 is the case. A good Morse chain seems to last through quite a lot. I've seen Ford pull truck cases where they were all hairline cracked... and they were pushing 1000hp.

    If I were really into the whole "doubler" or "super low range" thing I'd probably go SM465/drive's side NP241/divorced NP205 route. You'd have a very low range, the ability to run a pump off the 241, and the durability of all of them.
     
  9. az-k5

    az-k5 1/2 ton status

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    Here are some numbers for strength. These are from a recent issue of 4WOR.

    cross sectional thickness
    low-range side of the intermediate gear.

    ------------------- tooth length----tooth thickness----tooth shear area
    Dana 300 ------- 0.625 -------------- 0.310 -------------- 0.1938
    D300 w/LoMax- 0.625 -------------- 0.480 -------------- 0.300
    Atlas II ---------- 0.910 -------------- 0.275 -------------- 0.250
    NP205 ----------- 1.378 -------------- 0.333 -------------- 0.459

    LoMax is the 4 to 1 kit for the dana 300. The design of the 300 and 205 are simialr, but the size of the 205 gears is what makes it so strong. The 300 would be loosely comparable to an NP241 in a fullsize as far a dependable torque strength is concerned.
     
  10. marv_springer

    marv_springer 1/2 ton status

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    az-k5,

    Nice data.... that really answers the ? there.

    Mike,

    I would not put a D300 under a Blazer.... I don't think it would last.

    Go Atlas (maybe even be borderline - depending on who you ask /forums/images/graemlins/ignore.gif) or 203/205 Doubler....

    Marv
     

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