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NP205 to 700R4

Discussion in 'The Garage' started by K5dreamer, Aug 20, 2006.

  1. K5dreamer

    K5dreamer 1/2 ton status

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    Hey all, im lookin to swap a 4x4 700R4 into a 72 blazer with the NP205 transfer case to get the overdrive gear. anyone know what imma need to do that swap? do they bolt right up or am i going to need some sort of adapter?

    thanks in advance for any tips.
     
  2. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    you'll need a factory th350-to-np205 adapter + the ~2" spacer. I used one with my 700 for years, worked great. They are around $60. I forget the part #, but if you search, its out there.

    j
     
  3. Cricket

    Cricket 3/4 ton status

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    You might check with advance adapters: http://www.advanceadapters.com/ As far as I know there was never a 700 to 205 from the factory.

    Ooop, looks like Jek answered your question.
     
  4. chosen(1)

    chosen(1) 1/2 ton status

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    Which 205 do you need?
     
  5. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Would need to be a 27 spline 205 from behind a TH350.
     
  6. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    yeah, what he said... sorry I forgot about that part. ;) On the plus side, th350-version 205s are common and cheap. :thumb:

    j
     
  7. gmc4cw

    gmc4cw 1/2 ton status GMOTM Winner

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    If you buy a klune-v underdrive it will work as the adapter and give you another gear to choose. They are expensive though. But any input spline to any output spline is nice with a choice of ratios.
     
  8. K5dreamer

    K5dreamer 1/2 ton status

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    ok well the truck already has the th350 and np205 transfer case, so i guess i just gotta find that 2in spacer.

    second question, does this swap create any drivetrain angle problems or driveshaft length issues??

    i plan on putting a 4in suspension lift on the truck sometime down the road, would that complicate the swap?

    thanks again
     
  9. bigblock72

    bigblock72 1/2 ton status Premium Member GMOTM Winner

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    There are two options to adapt, the 2 inch spacer mentioned (usually found on 80s 350/208 combos) or get a short output shaft for the 700r4.
    This swap (especially if you use the spacer) will actually help the front drive line because it will be longer and will keep the u-joint angles liveable. I would recommend using a CV on the rear driveshaft to keep the angles and vibrations down to a minimum.
     
  10. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    You will need to lengthen the front shaft and shorten the rear shaft. The 700R4 is 1 7/8" longer than a TH350 and then you'll be adding a 2" spacer so you're going to be about 4" longer than your existing TH350/205. Driveshaft angle on the rear will be a problem that you will need to address right away or else you'll be getting a bad vibe. I would definately run a CV rear shaft.
     
  11. K5dreamer

    K5dreamer 1/2 ton status

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    good to know guys, thanks.

    you mention the CV rear shaft link. is that something i can just google, or do you reccomend a specific source for that part? also is it hard to install? i have an air compressor and probly most automotive tools nessesary, however i do not have a welder, and am not really experienced at the task. would this CV joint install be a bolt in process?
     
  12. bigblock72

    bigblock72 1/2 ton status Premium Member GMOTM Winner

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    You will have to have the driveshaft built the correct length with a CV (basicly two u-joints right next to each other allows higher operating angles, most front driveshafts use a cv on the front shaft on the t-case end.) You will have to change the yoke on the transfer case to correspond with the CV. So basicly once the shaft is built it is a simple bolt on deal.
     

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