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NP203 idea?

Discussion in 'OffRoad Design' started by Parf, Dec 5, 2001.

  1. Parf

    Parf Registered Member

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    Anyone consider making a 4:1 gear set for the NP203 gear reduction box? I don't know how feasable this idea is, but wouldn't that be cool? There are people making all sorts of replacement low gear sets for other transfer cases, why not this one? 3.06x4x2x4.56= 111.63:1 So...who's going to get right on this?
     
  2. Blazr77400

    Blazr77400 1/2 ton status

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    I was thinking the same thing. I thought about putting lower gears in the 205, but everybody said that they didnt have enough room. Probably the same deal with the 203. That would be bad as hell though.
    Maybe Just a 3 to 1. Because with the torque of my 6.2 Diesel,[​IMG] I would start breaking stuff.[​IMG]

    4 wheeling is like sex, when its good, its really, really good, when its bad its still pretty good.
     
  3. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    Parf,

    The closest you're likely to find.....simple and inexpensive.....Is the ORD-engineered solution of mating a 203 & 205 together to get the combined reduction of 4:1

    Follow this link:

    <a target="_blank" href=http://www.offroaddesign.com/catalog/doubler.htm>http://www.offroaddesign.com/catalog/doubler.htm</a>

    I've heard it from enough people who KNOW the NP205....that you can't get a bigger reduction gear in there....that's why you can't find it anywhere.



    -Greg72

    '72 K5 Blazer - 427BB/TH350/NP205/6" Lift/35x12.50's
    <font color=blue>See it here: </font color=blue><a target="_blank" href=http://coloradok5.com/gallery/albun38>http://coloradok5.com/gallery/albun38</a>
     
  4. Blazr77400

    Blazr77400 1/2 ton status

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    If you look at his post good enough, It has the Doubler setup configured into his crawl Ratio. Just with 4 to 1 gears in the 203 range box.

    4 wheeling is like sex, when its good, its really, really good, when its bad its still pretty good.
     
  5. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    Ok, I see that now.....

    I believe my comments are still valid whether it's for the 203 or 205 xfer case.....there is no room to add a significantly larger reduction gear to either one.....

    I think it becomes a "cost vs. benefit" issue, (minimal improvement, but costs big $$$$) which is why it hasn't already been done by someone.

    I could be wrong about all this....it wouldn't be the first time! [​IMG]



    -Greg72

    '72 K5 Blazer - 427BB/TH350/NP205/6" Lift/35x12.50's
    <font color=blue>See it here: </font color=blue><a target="_blank" href=http://coloradok5.com/gallery/albun38>http://coloradok5.com/gallery/albun38</a>
     
  6. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    We've started looking at the 203 a little, it's hard to get real carried away building gears for a case that was last built in 1979, but there's still a bunch of them out there. I'd like to have a 3:1 gear myself, I think it would be the most useful overall offroad gear, then you put the 205 in low and you really have something to crawl with. At 3:1, I think the 32 spline input would handle it OK.
    I know you can probably fit deeper gears in a 205, but how much do you want to pay for a minimal increase? I don't think a 2.5 gear set would be worth buying and I don't know if you could get that low without replacing all the gears. At that point the shafts are pretty cheap and you might as well build a new case and have a stronger atlas.
    i think there's a little room to play but the economics make it tough to justify.

    Making the world better, one truck at a time.
    SW-ORD
    <a target="_blank" href=http://www.offroaddesign.com>www.offroaddesign.com</a>
     
  7. Ryeguy

    Ryeguy 1/2 ton status

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    Yeah, you're at the point of diminishing returns. I'd say go for a home-grown version of the Klune-V (done it, it's not that hard). 2.72:1 low range stock, aftermarket gears are already available for 4:1 (though their strength is questionable). NP241 planetaries are strong, strong enough for a gear reduction box between the trans and an NP205. You can make one of these for a lot less than making a NP203 doubler, then getting a lower set of gears for it. Plus, the final assembly will be shorter (by a couple inches at least) than a NP203/NP205 combo.

    --Rob
     
  8. michaelm

    michaelm 1/2 ton status

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    how low is low enough?
    is 6:1 in the TC too low?
    how about 8:1?
    i dont have a doubler yet, soon, but not yet.
    to hear a doubler owner wanting another 2:1 in addition to what he has makes me wonder.
    I think it would be a better deal to have another unique gear.
    that is the only thing that the KluneV(must be made of gold though) has as an advantage.
    with the doubler you have 2 gear boxes at 2:1.
    if you had a 3:1 203 gear set you would have 1:1, 1.96:1,3:1,5.88:1

    is it cheaper to build straight cut gears in the 203? no reason to run helical in deep reduction
    i personally would rather buy replacement gearsets for my old worn out box that were deep then stock
    anyone done the math to see what you can get if you maintain stock input gear and just replace counter and driven gears, that would make it so everyone can use it rather then just you auto boys that ORD seems to cater to, plus only 2 unique parts...

    fairly certain the normal doubler will more then quench my thirsts. thank you for building and marketing it
     
  9. Ryeguy

    Ryeguy 1/2 ton status

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    Everyone has their own opinions on what is "slow enough". My personal hunch is that there is no correct "slow enough", and is best determined by the trails around you. 'Round here, ~60-70:1 is nice if you're running 'round 36's and have an engine that loves to idle along. Slower than that and you don't have enough momentum to pull you over the slippery rocks. But in Moab, you generally will want to be slower, I'm told.

    If you have the wheelbase, you could start stacking NP203's in there. Some locals also run a couple transmissions back to back to get super-low gearing with all kinds of gear combinations.

    Klune-V is expensive, but you can do it yourself for _lots_ less if you have a spare T-case with a good output shaft and planetary assembly.

    --Rob
     
  10. 79Beast

    79Beast 1/2 ton status

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    Let me ask everyone this: How often do you really use compound low? Running a granny four speed (if you have an auto it's your own fault) with almost 4:1 low and 5.13:1 or so axle gears gets you down to where I could walk on my hands faster than your rig is going. How long do you want to spend on the trail? How long until you multiply so much torque that even a detroited, chromoly shafted, 300M u-jointed, driveflanged Dana 60 won't hold up? Or is it just bragging rights?
     
  11. michaelm

    michaelm 1/2 ton status

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    who wants to drive around with 5.13s?
    my 4.88s are too low with 39" tires
    deep snow would be possible with deep reduction, kinda why Benie in Iceland built it and everyone else copied it.
    you can gear the axles to cruise the hiway, most likely stock gearing would work out, and have deep reduction for when you need it
     
  12. michaelm

    michaelm 1/2 ton status

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    took my 203 apart to check out the range box
    not much room on the rearward gears to enlarge, maybe a few teeth worth if that, but there is a bit for the input and driven to change.
    to get 3:1 by just changeing the size of the input and its mate you would have to reduce the input from 29 to 23 teeth and its driven gear grows from 32 to 38 teeth. most likely doesnt have the room in the case though
    useless trivia the input gear is 29 tooth driving a 32 tooth counter gear which spins a 23 tooth driving a 42 tooth speed gear
    looks like the next doubler kit should be stacking 2 203 rangeboxes in front of a 205 for the not easily pleased bunch
     
  13. Triaged

    Triaged 1/2 ton status

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    Would that be called a "Tripler"?

    '71 Blazer CST w/ a 400sbc, 4" lift, 36" Supper Swampers, and alot of rust
    <a target="_blank" href=http://community.webshots.com/user/triaged>See it Here </a>
     
  14. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Oh yeah, now I remember reading about the guy who came up with that idea first. Benny from "Bila bud Benna" which is "Benny's Off Road Store" in Iceland. [​IMG]

    He was featured and several of the trucks he built in Four Wheeler magazines a few times.
    Their whole philosophy is to keep the vehicle low and use massive tires that are aired down.

    Still fun to see and read about his trucks he has built. Nowadays, can't find anything to read about anymore because everyone stole his "original" 203/205 idea. Oh well, guess that's gonna happen if you don't patent anything right away. [​IMG]

    Thanks for reminding me about him. [​IMG]



    I'm not picking my nose...I'm just pointing at my brain!! [​IMG]

    <a target="_blank" href=http://coloradok5.com/gallery/thatK30guy>The K30 Collection</a>
     
  15. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    I thought I came up with a pretty good idea till I saw Advance using the 203 box on the toyota stuff, and heard about all the other uses of the NP203. Just goes to show you that really new ideas don't come along that often, most of what we all do is a variation of the existing.

    Making the world better, one truck at a time.
    SW-ORD
    <a target="_blank" href=http://www.offroaddesign.com>www.offroaddesign.com</a>
     
  16. michaelm

    michaelm 1/2 ton status

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    would love to hear the timeline on this stuff. just for the history and story.
    doesnt make a bit of difference who did it first, bet you got the highest number of them out there.
    I saw Benny from Icelands ford based stuff in print before I ever heard a whisper of it anywhere else.
    later saw AA TLC case but still havent seen them advertise that they do it.
     
  17. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    My story is:
    Saw a mag with a mention of the 203/TLC setup at some point in college, maybe '95-ish? Sometime concurrent to this I came across a 205 and spent some time looking at the blowup of it and a 203. The 203 blowup was conveniently layed out to easily suggest plugging the shaft into another 'case. So I just kind of filed it away. Then i graduated, goofed off for a few months and stared the biz and decided it might be a good idea to apply to the 205 so sometime around the spring of '98 I got it all together and installed the first one in my K5. first trip was to Moab for Mem. day, first obstacle was the dump bump, first broken part was a 297 joint. oops. right away I realized that I really like 4:1 t-case gearing but it did require a bit different driving. sometime that summer I met a new friend in Gunnison that had built himself a very similar setup a couple years earlier but had broken his non-heat treated shaft in Pritchett canyon, didn't sound like fun. I also ran across a guy in Canada that had done his own. both of the DIYers had messed up a couple of important details though and ended up with the only 2 shafts we've ever sold without adapters. Don't ask for them, the shaft is $740 so you might as well take the adapter.
    Sometime toward the end of last year we finally acted on the GEN2 idea that had been brewing for a couple years and built the first adapter sometime around Labor Day Y2K. Now here we are.

    Making the world better, one truck at a time.
    SW-ORD
    <a target="_blank" href=http://www.offroaddesign.com>www.offroaddesign.com</a>
     

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