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Doubler question

Discussion in 'OffRoad Design' started by spitfire, Jan 31, 2004.

  1. spitfire

    spitfire Registered Member

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    Mr. Watson,

    I have a Th400/205 combo in my 1-ton truck. I have a 32 spline range box, and a th400/203 adapter. I pulled this quote from your website. And it says that I need to use the Th400/205 adapter and redrill the face of the 203.

    [ QUOTE ]
    3: Use a TH400 that originally had a NP205 behind it. This TH400 uses a 32 spline shaft that sticks out about 4.5". You'll need to use a factory TH400 to round pattern NP205 adapter housing that is 4" thick and once again, re-drill the front face of the NP203 to match the round pattern. The input gear will be the TH400 version NP203 32 spline input. Drawbacks to this system are the overall length with the 4" housing between the two and the expense of buying the factory housing. They're not common as used parts and typically must be purchased new. ORD can supply this adapter.

    [/ QUOTE ]

    My question to you is:

    Can I use the th400/203 adapter I have, and cut down/respline the output shaft on the th400, to match setup #1?

    [ QUOTE ]
    1: Use a factory configuration. The TH400 was available with the NP203 in heavier duty trucks (3/4 and 1-ton generally) in approximately '78-'79. The factory configuration uses a 1 3/8" stickout 32 spline shaft in the TH400, a 32 spline input gear in the NP203 and a 1.1" adapter plate between the two, somewhat similar to the TH350 adapter plate. This is the shortest way to mate the TH400 and NP203.

    [/ QUOTE ]

    Thank You

    Kyle
     
  2. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    If you have a TH400/203 adapter that fits your 203 range box and the tranny originally had a 203 behind it then you will use the TH400/203 adapter / 203 range box / ORD doubler / 205
     
  3. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    You need to replace the shaft in your trans with the one originally used for an NP203. This will get you the right stickout for using the 1" adapter plate you have now. Unfortunately, you can't cut the 4 1/2" 205 shafts off enough to get it to work. I suspect you have the 4.5" stickout shaft in your TH400, it's the more common setup with a 205.

    We do have some customers that have cut the 2.5" shaft off and made it work with the 1" 203 adapter plate, so you could measure your output shaft up and see if it would work out. The 2.5" stickout shaft is found in TH400's with 205's from '85 up.
     
  4. thebigdaddyof2

    thebigdaddyof2 1/2 ton status

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    Stephen,
    (Not to hyjack the post but...)
    When talking of cutting T400 output shafts, have you heard of anyone having luck with modifing the output shaft of the 2WD (slip yoke) version?
     
  5. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    Not much knowledge of cutting the 2wd shaft but I know it's got a lot of spline length on it so you can probably get the 2.5" stickout with no problems, I just don't know about the 1.5" stickout. I took one apart a few months ago and didn't think to look at that when I did it. You'd have to measure it to find out for sure.
     

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