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doubler - 203 in low, 205 in high

Discussion in 'The Garage' started by muddybuddy, Dec 4, 2006.

  1. muddybuddy

    muddybuddy 3/4 ton status

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    i thought i read somewhere that this was a big no-no, is that so? why?
     
  2. 1979jimmy350

    1979jimmy350 1/2 ton status

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    i have heard that it is fine, i don't see why it would cause trouble
     
  3. sandawgk5

    sandawgk5 3/4 ton status

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    It is generally the procedure to keep the reduction as far down the line as possible to prevent breaking the input of the second case. The torque multiplication in the 203 can often time be detremental to the input on the 205. I have not heard of one actually breaking though.

    Ira
     
  4. Hossbaby50

    Hossbaby50 3/4 ton status

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    It is pretty common practice for the AZ guys. They love 2wd low & single low in the 203 4hi in the 205. Then when you need the extra gear you pop the 205 in low. You will be hard pressed to break a 205 with torque input even if it is doubled by the 203.

    Harley
     
  5. garlicbreath

    garlicbreath 1/2 ton status

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    But why would you want the 203 in low and the 205 in high?
    Why not just put the 205 in low?
    Unless your just wanting 2wd low or something.
     
  6. blazersnburban

    blazersnburban Registered Member

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    uhhh

    you answered your own ?....

    whats the difference of torque on the input shaft of the 205, if 203 is in low....no matter if the 205 is lo or hi? wouldn't it be the same either way.
    so why would anyone think it a no-no. thats how i get 2wd lo.....if i need 2wd lo-lo i put 203 & 205 in low and just don't lock hubs in.....helps when backing a trailer up in a tight spot! gives you plenty of time to turn steering wheel back and forth to manuver the trailer exactly where you want it!
     
  7. muddybuddy

    muddybuddy 3/4 ton status

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    i was wondering because if i do get a 3:1 box, i want to be able to have 1:1. 2:1. 3:1 and 6:1. if it puts extra stress on the input shaft of the 205, is there like an extra heavey duty one out there? the 3:1 would triple the tq, instead of double like a traditional doubler so i was wondering
     
  8. Greg72

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

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    The intermediate shaft (which comes with the Doubler) is the part that will be taking those stresses. It's a 32-spline dealio (typically) and IIRC the ORD ones may even have special hardening processes done to them as well. I've never heard of anyone breaking an intermediate shaft.

    You could always call Dr. Watson to ask the question, I suppose. :thinking:
     
  9. muddybuddy

    muddybuddy 3/4 ton status

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    yea i didnt think it would be a problem, since it is 32spline. and i supose if by some act of nature the thing does break, it would only destroy the intermediate shaft right? so could just get a new one and be on my way, or would it destroy the cases?
     
  10. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    I believe it's in thew Doubler info page on ORD's site where it says don't do it. sandawgk5 is right, you want the reduction as far down stream as possible.

    As for the difference in torque question by blazersnburban, you'd be putting 2x the torque into the 205 that it was designed to handle since no OE app has an upstream reduction device.

    Imo, if you've got to buy it all anyway go with a 2:1 Doubler + Lomax and triple stick it for 2wd lo.
     
  11. Hossbaby50

    Hossbaby50 3/4 ton status

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    I believe what they tend to do is cruise around on the trail threw the easier stuff in 2wd low in the 203. If they hit a little rough spot the click the 205 from 2hi to 4hi so the get 4wd when they need it but then they click back to 2lo for the ease of steering & such. Then if they need double low they pop it in neutral & put the 205 in low also.

    Harley
     
  12. marv_springer

    marv_springer 1/2 ton status

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    205 + 32 spline input = pretty much indestructable....

    This is why using anything but a 205 [or super-duper aftermarket model] for the 2nd case becomes questionable.

    Marv
     
  13. miniwally

    miniwally 1/2 ton status Premium Member

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    This is exactly the the Deal. The intermediate shaft is strong but it is still the weak spot in the system. The shafts from the major suppliers are all some sort of billet good stuff that is hardened to make them stronger.

    These shafts have broken. Like 1 or 2 that I know of from different suppliers. They both broke when the owner had the 203 in low and the 205 in high and got on it. I think they were both behind built big blocks and there might have been other factors involved.

    Bottom line is when possible don't put the 205 in high and the 203 in low.
    I put mine in 4:1 and leave it there most of the time. I use the tranny to get higher gears not the t-case. If I want 2:1 the 203 is the easy to shift unit not the 205 so it always gets shifted first.

    This is a problem though if you run a 3:1 box. Then you are forced to use the 203 in low and the 205 in high if you want the 3:1. Just be careful.
     
  14. muddybuddy

    muddybuddy 3/4 ton status

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    yea thats what i thought. the doubler is going to be behind a 6.2 diesel, which may eventually get turbo'd, but its not going to be getting mad high rpm's. in the instances when the intermediate shaft did break, was it only the shaft that broke? like were the guys able to get a new intermediate shaft and be alright, or did it cause any damage to either cases?
     
  15. muddybuddy

    muddybuddy 3/4 ton status

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    also, when running in 6:1, is that going to put alot of added stress on the 205 outputs? would it be smart to upgrade to 32spline outputs, or should the stock ones be fine?
     
  16. miniwally

    miniwally 1/2 ton status Premium Member

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    I don't know what all broke. I got the story second hand. I think that it was only the shaft and nothing else big and major.

    Upgrading spline count is always a good idea but I couldn't tell you if it is mandatory or not. I know that Stephen with ORD could, NWF should be able to shed some light as well.
     
  17. muddybuddy

    muddybuddy 3/4 ton status

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    thanks alot man, yea hopefully they will chime in soon. im going to go with one of their adapters, so if they havent asnwered my question by then ill ask them when i order it.

    i havent checked mine, but what are the chances i have the weak 10spline front output? the 205 ive currently got is a round pattern, with a ford 31spline inpust swapped into it, ill probably end up swapping to a 32 just do i can get that extra spline, every one counts.
     
  18. miniwally

    miniwally 1/2 ton status Premium Member

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    I really don't know much of anything about the stock form of the t-cases.

    I just know what the good parts are. Sorry
     
  19. muddybuddy

    muddybuddy 3/4 ton status

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    :haha: :haha: apparently oem is not good:D
     
  20. NorthWestFab

    NorthWestFab 1/2 ton status

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    The reasoning stated on 'reduction down the line' is probably where the suggestion came from. Without being re-geared, the 203 and 205 are the same ratio, so given the option I can see why it is suggested to run the 205 in low instead.

    Is it going to cause any problem running the 203 in low and 205 in high ? I've never had a shaft broken from *any* use, including 23 spline for my D300 kits. Same goes for ORD I believe.

    Like i said, I can see where the suggesgion came from, however I'm yet to see any breakages, so I don't see much reason for concern. If you ran a LowMAX or BlackBox, you'd HAVE to engage the initial range box to take advantage of the varying gear ratios.

    -Kyle
    NWF.
     

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