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Transfer Case ID Help

Discussion in 'The Garage' started by bridgeguy, Oct 3, 2005.

  1. bridgeguy

    bridgeguy Registered Member

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    I've looked through a ton of threads, I've looked at the specifications page on the home page of CK5, and I'm waiting for my Chilton's to show up. With that said, I'm looking to find out something so stupid and obvious that I feel like an idiot for asking:

    I have a '74 K5 with a TH350 (I know what the pan looks like through the crud and can ID that). The specs page says that the automatics in '74 were a 205, but the transfer shifter shows all 4WD with no 2WD.

    With the junk gunked up under this thing (I've never had it running yet so can't tell if it's accurate but from the way the rest of the Blazer looks, it should be) I can't really tell what the transfer looks like. In all honesty, I'm new to working on 4WD so I probably couldn't tell it I could see it.

    Can anyone give me the quick and dirty on what this might be? 203 or 208 is my guess, but that's all it is...a guess.

    Thanks for your help with a downright stupid question. Maybe I'm just tired and not thinking straight right now. That would be preferable to be honest.
     
  2. fatbob

    fatbob 1/2 ton status

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  3. txfiremank5

    txfiremank5 1/2 ton status

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    Does it go:

    lo lock
    lo
    N
    Hi
    Hi lock

    If so, it's a NP203.
     
  4. dremu

    dremu Officious Thread Derailer Premium Member

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    Autos in those years came with a 203. *Sticks* came with a 205.

    Check out Chuck's page on this ... the 205 has the third, smaller, round cover on the back, with the three bolts on it.

    Yours I am willing to bet is the 203 and doesn't have said cover.

    Don't ask me why I know this :doah:

    -- A
     
  5. monster man

    monster man 1/2 ton status

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    "Autos in those years came with a 203. *Sticks* came with a 205"

    not always- my dad bought his (now mine) '73 Cheyenne Super with a TH350 and NP205............ I think the cutoff was mid '74, but most all Blazers came with a 203, never say never though. . DO you have locking hubs on the front wheels? If not it's a 203 (though kits are also available so if you do have them that doesn't mean it's a 205). The 208 didn't come out til the early 80's so unless it was swapped in it's a 203 or 205.
     
  6. bugspray

    bugspray 1/2 ton status

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    That's a great link. For as many times as people (myself included) ask this, that's a great one to refer them to.
     
  7. Executioner

    Executioner 1/2 ton status

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    It can not hert to guess right ?
    I guess is a NP 203
    FYI if it does turn out to be a NP 203, please run motor oil
    in it.
    Good luick


     
  8. bridgeguy

    bridgeguy Registered Member

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    That would be it. It's what I feared then. Although, I prefer to think of it as being half-way to a Doubler. :crazy:

    I was leaning towards it being a 203, but the specs pages here were saying 205 only for a TH350 and I was pretty sure I couldn't get that lucky.

    Next question would be: Milemarker makes the part-time conversion kit(s). From what I understand, I need to get the new hubs (any of them that fit on this thing, looking at Warn Premium), and then get a conversion kit as well? What happens if you don't have the conversion kit, and which one is a better one keeping in mind that I'm looking at eventually getting a Doubler or changing over to a 205 at the minimum? I saw one with a shaft replacement and another that just looked different on the Milemarker website. Any ideas on the preferred one and why?

    Also, why would you want to run motor oil in a 203 and what weight?

    I'm an engineer, I've got to know the piddly little answers or they drive me crazier.

    Thanks for your help.
     
  9. dremu

    dremu Officious Thread Derailer Premium Member

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    A fine way of considering it! :D

    The Warn Premiums are good, yes. You can use any brand hubs you like.

    The part-time kit ... eh. I wouldn't spend any $$ nor take the time to pull the 203 ... they're FREAKING HEAVY (that's an exact measurement of mass, for you engineers :haha: ) and it's a major PITA.

    For the alleged decrease in miserableness of fuel economy and wear-n-tear on the drive train, I'd put manual hubs on and call it good. Especially if you're gonna go Doubler or '205 eventually, no reason to throw good money at a '203 which is essentially worthless.

    Oh, and search on the motor oil thing; I use 30wt in mine. Originally GM spec'd gear oil in there, but the lighter weight stuff should help you a very tiny bit in the fuel economy department.

    -- A
     
  10. txfiremank5

    txfiremank5 1/2 ton status

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    I always had good luck with my 203.

    As for the conversion kit... what are your plans. The reason I ask is: are you planning to keep it mostly stock... or upgrade? If your future plans include a doubler, I might assume they may also include larger axles? If that's the case, I'd probably live with the fulltime for now. I kept mine fulltime from 83 when I got it, until 99 when I sold it. Most of that time it was a daily driver. I'd just stay that way until I knew what I was going to do for sure. No sense spending money and then swapping in something different a year later.

    Motor oil is what Gm spec's in it, if I rememebr correctly. It's been a while. :crazy:
     
  11. Executioner

    Executioner 1/2 ton status

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    I don't think so......................
    Please show some data on GM spec'd gear oil.
     
  12. destinbeachman

    destinbeachman 1/2 ton status

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    I run 20w50 in mine and it's still alive after a few years behind a bbc,although it's showing some play.Good thing I have a doubler on the way :D Anyway,from what I have been told and after being inside mine,the 203 relies on the chain to help spread the oil around inside the case and the heavier weight gear oil won't splash around enough to lubricate the upper half of the case.The lighter weight motor oil does the trick.
     
  13. diesel4me

    diesel4me 1 ton status Premium Member

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    motor oil...

    My old "Veedoil" lube spec chart says GM reccomended 10w-30 or 10w-40 motor oil...my chiltons manual says 20w-50 motor oil...none of my books reccomend 80w90 for the NP203--just some NP205's..(Some 205's use Dextron ATF!)...

    But I've drained a lot of T-cases,and many didn't have the right lube in them--none of them were in for anything but oil and fluids changes,and had anything wrong with them!..I can see where 80w90 could damage a NP203 or one of the later NP208's in cold weather though..stuff is like grease below 32 degrees!..but I guess ANYTHING is better than empty! :rolleyes: :crazy:
     

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