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ford vs. GM np205 almost the same?

Discussion in 'The Garage' started by 84gmcjimmy, Oct 12, 2004.

  1. 84gmcjimmy

    84gmcjimmy 1 ton status

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    I found what I think is a great write up with lots of pics on how to rebuild a np205, but its a ford np205. Is it pretty much the same as rebuilding a gm np205? (what I have) or is the rebuilding process completely different?
    Thanks
     
  2. boz42

    boz42 1/2 ton status GMOTM Winner

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    they are the same in my expeirence, just mirror images of each other
     
  3. 84gmcjimmy

    84gmcjimmy 1 ton status

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    okay good.
    On rebuilds, what parts do people usually replace to make the internal parts even stronger (if they do) or what they replace?
     
  4. m j

    m j 1/2 ton status

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    you can change the front shaft to a Ford 32spline version
    I cannot recall anything else for strength
     
  5. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    That's pretty much it. The 32 spline front output is a good upgrade. All Fords have a 31 spline female input equal to the 32 spline GM (so you don't need the rare Th400 input for a doubler). I used the Ford input in my doubler 205. And AFAIK, all Fords have a fixed rear output. Only problem there is that it can be difficult finding the right speedo drive gear. IIRC, there was only a very small range of years where you could find the correct gear to work with a GM speedo on the Ford output. That would need more research because I don't remember the specifics...
     
  6. JK5

    JK5 1/2 ton status GMOTM Winner

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  7. 84gmcjimmy

    84gmcjimmy 1 ton status

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    Okay, should I have to change any parts inside, or replace anything? What should I replace? Thanks
     
  8. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    If I understand you correctly, that's a complicated question and depends on what you want. For the vast majority of things the stock GM 205 is just fine and you won't *need* to replace anything but seals and gaskets. Just check for wear and damage on the rest, but it's usually fine. Exceptions where you may find wear/damabe may be the input splines (especially 10 spline) or (unlikely) the front output. The rest is just common sense, do you need stronger? That's the question to ask yourself. There are not cut and dried answers.
     
  9. 84gmcjimmy

    84gmcjimmy 1 ton status

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    Okay. When I start to take it apart, I will make sure everything is in good condition, with no signs of excesive wear. If everything is good, I will just replace seals and gaskets.
    By the sounds of it, it should be fine if I dont replace any of its parts, except swap to the ford 32 spline, because I will be running around 400hp, not excessive like a mudbogger with 1000+ HP. So I;m pretty sure it will last /forums/images/graemlins/woot.gif

    Thanks for the help guys
     
  10. m j

    m j 1/2 ton status

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    you do not even need a 32 spline ford in that application
    though it is a good upgrade for reasons other then strength as well
    will accept the same yoke as the rear output, so reduced parts inventory
    will allow you to use a bigger then stock Chev, yet still cheap OEM 1330CV joints from a Ford, or even a huge 1410 u joint if you choose to run no CV

    I do not recall what year the 205 that you are working on is but I would bet you need to change nothing major on it for your application.
    as long as it isnt a slip yoke style I would just inspect and reseal it.
     
  11. atho

    atho 1/2 ton status

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    From what I have seen, the 10 spline input gear seems to hold up on the NP205s (and Rockwell T221's also, fwiw). It is the SM465 10 spline output and coupler sleeve that end up wearing on each other. The suburban I got one of my NP205's from had worn the 465's output shaft down so badly, the splines had edges you could shave with (or cut fingers on /forums/images/graemlins/angryfire.gif ), but the input gear looked brand new. The Rockwell originally in my truck was the same way, but not quite as bad as that burb.
     
  12. bigblock44k5

    bigblock44k5 1/2 ton status

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    While you have it apart do yourself a favor and replace the bearings. Yea it will cost a litlle more, but its just trashy in my opinion to open it up and not replace the bearings. My bearings went after I had already twin sticked it and put it back in my truck, now im not looking forward to pulling it again. Gears should be fine, just check for obvious failures, to include bluing on gears and surfaces due to overheating. Good time to twin stick it also if you want it.
     
  13. 84gmcjimmy

    84gmcjimmy 1 ton status

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    Okay, I will spend the extra money and replace bearings too. And I will check for the discoloration (bluing) on the gears for overheating.
    Thanks for the help
    Oh, and I plan to triple stick it anyways.
    M J, its a slip yoke right now, I will be changing that when I rebuild it. And I dont know the year of it, I will ask Kevin (crazykev4x4, the guy I bought it from) .
     

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