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203 or 205

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by reddog64, Oct 5, 2001.

  1. reddog64

    reddog64 1/2 ton status

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    OK... so in the buildup of my current project it's come time to decide on either the 203 or the 205 xfer case...

    Anyone have a favorite???

    The 203 would need a part tiem kit...
    Does the 205 need a part time kit???
     
  2. K10ANDYKHAMNIC

    K10ANDYKHAMNIC 1/2 ton status

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    go 205 ! 203 is poo caca unless u have a doubler(tm) from ord (tm)

    WHATS WRONG WITH A 305 ?
    81 K10 GOODYEAR 35" MTRS
    TH350 NP 208
    STEPHENS OLD AXLES
    NO BREAKAGE :)
     
  3. EDdaTREE

    EDdaTREE 1/2 ton status

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    Actually, a 203 is almost as strong as a 205. They're both cast-iron cases. You can actually run 203's forever before the chains let go. I've been running fulltime 203's with lock-outs on the front axle to make a full/part-time system for years with no bad effects. The 203 is so cheap and plentiful, I've had many GIVEN to me for FREE!! I'll never even bother with a 205, even though I could get one from a buddy for $200.

    9/11/01..Never forget...Never forgive
     
  4. kchecca

    kchecca Registered Member

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    So do the hubs bolt right onto the front in place of the full-time units. The case would still be turning the front shaft and axle, but it wouldn't be coupled to the wheels? I like this!

    --------------------------
    Keith C
    Bigbird '00 Jeep TJ
    Grandpa's '77 Blazer
     
  5. EDdaTREE

    EDdaTREE 1/2 ton status

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    kchecca...exactly right. Only difference is you have to run the transfer case in a LOCK position when hubs are un-locked or the front driveshaft will spin and truck goes nowhere fast. This LOCK position locks front and rear driveshafts together, other-wise torque goes to the least resistant place, the free-spinning front shaft.The main difference between a 203 and 205 is the 203's lockable differential inside the case. For Ohio's screwy weather, I can lock my front hubs and run it in 4-HI, resulting in full-time 4wd for street usage. Off-road, I run locked hubs and HI or LO-LOCK position, locking front and rear shafts together at the T-Case. You may read or hear that this is bad for the case, but I've done it for years with no problems.

    9/11/01..Never forget...Never forgive
     
  6. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I would think that driving a 203 that way wouldn't be a good idea. In my opinion, it'd be like driving with an open front diff and one hub unlocked with a part time system. There's some kind of differential front to rear in a 203 that makes it full time, and you might burn that part of it up doing what you're talking about. I don't think there'd be that much gas mileage increase anyway, and if it damaged your 'case, it definitely would not be worth it. I know nothing about NP 203's internals, but depening on how the center differential works, that might not be a good idea.

    I would suggest you get the 205 if it's an option. It has the same low range as a 203 and it doesn't have a chain. I don't see the point of not getting the toughest parts you can. If you've already got the proper 203 though, it might be worth it just to keep it.

    I am using a 205 when I put my 4 speed in. I'd do about anything to get rid of my 208. I won't really miss the low range (6.55:1 first gear) and the 205 is basically indestructable when compared to my other driveline components, and the fact that my engine only puts out 330 ft-lbs.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  7. HarryH3

    HarryH3 1 ton status Author

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    Think of the diff inside a 203 as an ARB or Ox Locker. When it's locked there is NO differentiation.

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
    It's a great day to be alive...
     
  8. BIGRIG

    BIGRIG 1/2 ton status

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    BOTH! go with the doubler and then you wouldn' have to decide!

    MY DRINKING TEAM HAS A FOUR WHEELING PROBLEM![​IMG]
     
  9. BorregoK5

    BorregoK5 1/2 ton status

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    I understood that the LOCK position distributed equal power from front to rear and that the H or L position was path of least resistance. I've even noticed the difference in the locked position. Strangley enough, I run my front hubs unlocked most of the time and regardless of what position I'm in (LLOC, L, H, HLOC) I always send full power to the rear wheels. For some reason, it never occured to me that this shouldn't happen in the L or H positions but... now I'm stumped! Is there something I'm missing here, perhaps my 203 has had a part time kit installed by the previous owner???

    "I'm looking for a Dana60 Front Axle.." I asked, "You wish! HAHA" the wrecker replied! - <a target="_blank" href=http://www.echobit.com:81/k5/> Pictures</a>
     
  10. EDdaTREE

    EDdaTREE 1/2 ton status

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    Borrego, your 203 must be already converted to part-time. An untouched 203 will always dump power off the easiest way unless locked. I understand what the previous poster was saying, I've heard the sme thing a million times.

    9/11/01..Never forget...Never forgive
     
  11. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    Ain't nothing to converting a 203 to a part-time case. You just put in a few stops and you can have 2 or 4 wheel just like a 205. I think mile marker makes the kit. The only thing you have to do is run the case is 4-wheel drive every few hundred miles to keep things lubricated.

    <a target="_blank" href=http://www.geocities.com/bigkern76>http://www.geocities.com/bigkern76</a>
     
  12. elkboy

    elkboy 1/2 ton status

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    A 205 is lighter and stronger than a 203. You can rebuild a 205 in a couple of hours, simple all gear design. You will pay a little more for a 205, but it will be worth it. I wouldn't overlook a TH400/208 combo either, they are fairly common, cheap and strong.

    <font color=red> Elkboy </font color=red> 82 K5 fuel injected H.O.305, TH350/205, 14bolt/10bolt and 39.5 TSL's.
     
  13. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I didn't think about that. I guess you'd have to drive in the 4 hi lock part of it with the front hubs unlocked, otherwise all the power would go to the front axle because of nearly no resistance. And yes, I know, in 4 hi lock, there'd be a 50-50 split just like a part time system.

    Like I said, I don't see the point. How much gas could you possibly be wasting by leaving the front hubs locked and driving it in full time 4wd compared to just turning the front driveshaft, pinion, carrier, and shafts?

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  14. jwduke

    jwduke 1/2 ton status

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    Tim, I had a NP203 in a '76 GMC, I put a part-time kit in it from Mile-Maker. My fuel mileage went from 10 to 12 mpg. Plus I had MUCH better take off power. A added bonus of putting a parttime kit in a NP203 is you gain low 2 wheel drive. You don't have this with any other transfer case currently built!

    1 ton '87 Chevy SWB in the making!
     
  15. chevyboy24598

    chevyboy24598 1/2 ton status

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    I've got a similar problem, exept my 203 goes into front wheel drive.


    Rust=Good
    <a target="_blank" href=http://www.bodatious.com> bodatious </a>
    <a target="_blank" href=http://www.mudboggingfun.homestead.com> my site </a>
     
  16. EDdaTREE

    EDdaTREE 1/2 ton status

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    Chevyboy...never heard of that one..LOL!! You sure your fronts aren't just spinning a bit because of the weight shift taking off? Try front wheel drive in reverse, see if the rears spin. Actually, you can do 2-lo on a 205 by doing a mod on a small detent piece in the shifter? part..I believe.

    9/11/01..Never forget...Never forgive
     
  17. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Here's a link to the twin stick a 205 article...[​IMG]<a target="_blank" href=http://www.geocities.com/tom-p/Temp/> Twinstick</a>
    Right now if I want 2 Low, I just don't lock my front hubs...[​IMG]

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
     
  18. EDdaTREE

    EDdaTREE 1/2 ton status

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    THERE'S my Canadian brother!! 'Bout time ya got back on here and shared your wisdom!

    9/11/01..Never forget...Never forgive
     
  19. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I've been here on and off...checking cam specs out for KRAZIE87K5.

    I love the engine analyzer program...[​IMG]

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
     
  20. chevyboy24598

    chevyboy24598 1/2 ton status

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    I know its in front wheel drive because: when I unlock the hubs it just sits there with the front drive shaft turning.


    Rust=Good
    <a target="_blank" href=http://www.bodatious.com> bodatious </a>
    <a target="_blank" href=http://www.mudboggingfun.homestead.com> my site </a>
     

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