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Possibly the cheapest O/D unit ever??

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by AussieK5, Oct 19, 2001.

  1. AussieK5

    AussieK5 1/2 ton status

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    After searching around for a locally made O/D unit and encountering exorbitant prices coupled with questionable strength, I had a blinding flash of insight, and I've rushed home to ask you guys this question.

    What about a range box from a 203 reversed and divorced, mounted behind my transfer case with a customed up yoke on the side that needs it?

    I don't have a 203 to tear apart and need some thoughts from those that have rebuilt them.

    My thinking is that I need about .7 gearing as a suitable O/D gear. Why not use the 203 range box to split third (465 3rd= 1.57) for a 'tranny' that would give approx 2000 revs at hwy speed with my 4.10 on 33's.

    Obviously some fabrication is required (oh my and theatrical sigh! any excuse to break out the tools) for a mounting device and/or cradle....also the yoke setup, does the range box have two male output shafts???......anybody with experience here feel free to burst my bubble, would it work??

    Some things which could cause problems are....are the gears straight cut?..how would they handle running backwards?......will I be able to shift at hwy speeds?

    Well thats enough rambling from me, what do you think?
     
  2. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    You could do it like a doubler...with the range box reversed behind the tranny then into the 205. There is a company here that has done it at least once for a truck running Mog axles. The final drive on the Mog axles is 7.46 to 1 so for the street the 203 OD unit[​IMG] is left in OD, for offroad you would have two choices for 'crawl ratio'.

    The place I saw this info is <a target="_blank" href=http://www.customtruckshowcase.com/forum/showthread.php?s=&amp;threadid=174> here</a>

    The thread is about Mog axles...but includes info about the reverse 203 range box farther down. Poster with the info is Taradon

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
    <a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>
     
  3. AussieK5

    AussieK5 1/2 ton status

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    Thanks for the info, it's encouraging to see someone has run the case in reverse before.
     
  4. Ddragggon

    Ddragggon 1/2 ton status

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    heynow, thats what I;m talking about....

    I wanted to run a full transmission in reverse, but never could figgure out if it'd fly appart from the torque or not... putting in a reversed NP203 rangebox sounds to me like a MUCH better plan....

    WHERE IS THIS OTT ENGINEERING? anyone know? please let me in on the secret... :-)

    thankyou, and talk to you all later,

    -Rich

    My truck isn't ugly, you have a skewed sense of beauty

    <font color=blue>2007 Ford XLS++ intrepid Ram Superduty 7000 R-type's suck</font color=blue>
     
  5. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    OTT is in Burnaby BC...about 30 minutes from me. Local is cool, but I'd still prefer to use ORD if possible.

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
    <a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>
     
  6. Nonesuch

    Nonesuch 1/2 ton status

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    man those mog axles are sweet. 6.5" more clearance than a d60 at the pumpkin and only an extra $500 over the normal cost of a matched set of used 1 tons. that is a killer deal! trusty have you done the math on this set up with the reversed 203 yet. I would be interested to know what you have come up with so far! Where you planning on running some mog axles?

    Justin
     
  7. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I'm in the early stages of seeing how much work it might be, right now I'm worried about getting the truck too tall. The pumpkins are only 3.5" offset from center, so you need a bit of lift to make the drivelines work out. The front is a drivers side pumpkin so I guess a ford or Dodge 205 would be required. I haven't verified the reverse driven 203 range box yet, so far the info I have is second hand. I guess the other alternative would be a Klune-V OD unit hung off the back of a 205 for OD on pavement...

    Those Mog axles do have me interested though...the guy that sells them is local to me so they would actually be less expensive than one ton stuff, especially if you count in shipping and cross border BS. I'd need custom rims made for it though. It's a wierd metric 6 lug pattern, huge lugs too.

    Still doin the research...as I find stuff out I'll post updates.

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
    <a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>
     
  8. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    This was discussed on the ORML (off-road mailing list) a while back, but with a 205 not a 203. Don't know if it would make a diff. Either way you might mant to post there for ideas. Offroad@offroadlist.com Lots of great people on there.


    Jim '80 GMC & '73 Blazer
    Body by Tellico
    <a target="_blank" href=http://www.tellicok5.rockcrawler.com>www.tellicok5.rockcrawler.com</a>
     
  9. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Thanks dude...I'll have to check it out.

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
    <a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>
     
  10. pcorssmit

    pcorssmit 1/2 ton status

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    Hey Rene, wasn't sure if you'd seen this or not.

    http://www.sierrarockcrawlers.com/main.html (Can't figure out how to get a direct link to the page, but it on the 1 ton forum, the post is "Bet you cannot name this axle!!")

    They had a pretty good discussion going about portal axles. Its come up on Pirate last couple days, too.

    As for the height issue, what about going leaf-under? Not sure if the frame clearance is there or not, but I think you'd either have to go to a link type suspension or a leaf under to control the axle wrap.

    Pete

    '83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
    '97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
     
  11. AGM73k5

    AGM73k5 1/2 ton status

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    Clicky: <a target="_blank" href=http://www.sierrarockcrawlers.com/main.html>http://www.sierrarockcrawlers.com/main.html</a>
    -Aaron

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    AGM73k5 -- ajgm1@yahoo.com
     
  12. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Hey Pete...thanks for the link!

    As far as I understand the height between the frame and the axles is somewhat critical due to the pumkins only being offset by 3.5" from center. If you don't have enough height the driveshaft will smack the oilpan. Ideally the Mog front would have the same offset as a D60...but that would be too easy [​IMG]
    The rear Mog axle is also offset 3.5" from center, but it's not as big of a deal as the front.

    I think for staying somewhat low with 39.5's I'll have to stick with the D60...

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
    <a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>
     
  13. RedDwarf

    RedDwarf 1/2 ton status

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    Great link Rene. That site is very cool! [​IMG]

    Still Poundin' "pavment" after all these years!!! [​IMG]
     
  14. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    [​IMG] yup, good stuff there. Have you considered joining up?[​IMG]

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
    <a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>
     

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