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NP 203??s

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by DesertDueler, Feb 25, 2002.

  1. DesertDueler

    DesertDueler 1/2 ton status

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    Well I got a th400-203 combo that I was going to use for a doubler, but I might not since switching to a doubler and swapping my gears back to where I can drive it will put the crawl ratio the same. th-400, doubler, and 3.73 are the same as a 700r4, 208, and 4.56s. So I was thinking about putting it into the Burb since its getting 1 ton axles. Well how is full time for gas milage, and is it true that converting it to part time wears them out quicker? Thanks for the help, I dont really know much about the 203s.

    86Jimmy 4"&35"MTRs,87 burb 4"&33"MT,69Firebird w/525 hp,and 70GTO live in PHX,AZ<a target="_blank" href=http://www.geocities.com/modifierperformance>My vehicles</a>
     
  2. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    on my blazer with 3.73 and th350/203 i got about 12 on HW with a crate motor. and about 9 in the city. now you want to put in a burban, make sure you change it over to part time, and i would recomend buying the shaft, not the "clutch" for the conversion. it cost a lot more but is a lot better.
    my buddy runs 4.11 and a th350 with a part time 203. he gets a lot better than i did. dont know exact number but it is like 15 and 12 i think.
    Grant

    take me drunk, i am home
    www.geocities.com/seventy4blazer/parts4sale.html
     
  3. DesertDueler

    DesertDueler 1/2 ton status

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    Where do I get the shaft conversion. I only use my burb for towing, and I need 4wd to put my boat in the water. I dont drop it in at a ramp, I drop it in at coves so I need a good working 4wd or I'll get stuck.

    86Jimmy 4"&35"MTRs,87 burb 4"&33"MT,69Firebird w/525 hp,and 70GTO live in PHX,AZ<a target="_blank" href=http://www.geocities.com/modifierperformance>My vehicles</a>
     
  4. BigTex

    BigTex 1/2 ton status

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    You can get the part-time conversion from Summit or pretty much any mail-order catalog. There are 2--an expensive one and the one for 50 bucks. I don't know of anyone who has the more expensive kit. I have the 50.00 one along with the Warn hubs and let me tell you--there is a HUGE difference in gas mileage. It will pay for itself very, very soon. Mine paid for itself in a couple of months. I highly recommend it.

    <font color=red>"PROCRASTINATE NOW!!!"</font color=red>

    <a target="_blank" href=http://coloradok5.com/gallery/BigTex-Mean-Machine>http://coloradok5.com/gallery/BigTex-Mean-Machine</a>
     
  5. BigTex

    BigTex 1/2 ton status

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    And to answer your question--a full time 203 on a Suburban would be a killer on gas mileage. I really noticed a major difference in not only gas mileage, but front tire wear as well.

    <font color=red>"PROCRASTINATE NOW!!!"</font color=red>

    <a target="_blank" href=http://coloradok5.com/gallery/BigTex-Mean-Machine>http://coloradok5.com/gallery/BigTex-Mean-Machine</a>
     
  6. Redfrog

    Redfrog 1/2 ton status

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    I put in the shaft kit, and it was easy, I bought it <a target="_blank" href=http://www.macromotive.com/shopping/goShopping.cfm?tag=3.1.103.152.2977.0>Here</a> the cheapest place I found, but you have to buy a oil pump gear from GM it was I think $6.00












    *wink*

    my 79 rust bucket will run over your 2001 chevy 4X4 tahoe plastic wagon
     
  7. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    What did the kit include? I just bought a K10 with a 203 that has been converted. I assume they used the "cheap" kit. I don't need hubs, I just need the shaft, do they sell that seperately (just the shaft)?

    edited: The reason is I plow and have heard there are strength issues with the cheap kit. I would like to rebuild the whole case (as it has 200,000+ on it) and want to put in the heavy duty shaft in.
    See my rig at &lt;a target="_blank" href=http://coloradok5.com/gallery/Leadfoot&gt; click here &lt;/a&gt;<P ID="edit"><FONT class="small">Edited by Leadfoot on 02/27/02 07:38 AM.</FONT></P>
     
  8. Redfrog

    Redfrog 1/2 ton status

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    the kit included the shaft and the gasket for the second half of the tail cone there is a o-ring in the first part of the tail cone
    (where the speedo screws in) When I put mine in I rebuilt it
    and bought the gaskets, O-rings and seals from ORD
    I think for $40.00 once again best price I could find. this might help you a little <a target="_blank" href=http://www.off-road.com/chevy/mm-np203/>http://www.off-road.com/chevy/mm-np203/</a>
    Hope this Helps

    the only thing I was not happy with is that Mile marker did not Debur the shaft the were burrs on mine that were 1/8 of a inch tall [​IMG]



    *wink*

    my 79 rust bucket will run over your 2001 chevy 4X4 tahoe plastic wagon&lt;P ID="edit"&gt;&lt;FONT class="small"&gt;&lt;EM&gt;Edited by Redfrog on 02/27/02 12:08 PM.&lt;/EM&gt;&lt;/FONT&gt;&lt;/P&gt;&lt;P ID="edit"&gt;&lt;FONT class="small"&gt;&lt;EM&gt;Edited by Redfrog on 02/27/02 12:10 PM.&lt;/EM&gt;&lt;/FONT&gt;&lt;/P&gt;<P ID="edit"><FONT class="small">Edited by Redfrog on 02/27/02 12:12 PM.</FONT></P>
     
  9. weisel

    weisel 1/2 ton status

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    I went to the link Redfrog put up, and that is not the piece that I have in my part time 203. Mine takes the spider gears out and rides on the 4 shafts they rode on, and on the other side has a recessed gear cut in it that solidly locks up to the rear output shaft. The whole gear is probly only 2.5" in diamiter and 3" tall. I don't know if this is the cheep one everyone is talking about, but it is not a clutch. I don't see a way to break it, it is pritty heavy duty. I don't know who sells it cuz I got it with the truck, but you might want to look into it, might be less expencive.

    No, thats not a dent in my truck's body. I call it my truck's armor.
     

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