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NP208 to NP205 swap...

Discussion in 'The Garage' started by jonrpick, Jan 26, 2007.

  1. jonrpick

    jonrpick 3/4 ton status

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    What are the differences in size between these two cases, assuming they both came out of a Chevy truck (not a F.O.R.D. or other version...)??? I'm just curious whether I'd need any adapters or a longer/shorter driveshaft or anything. It'll be bolting on the back of a 700R4.

    My 208 has metal shavings in the oil, and I found a 205 locally for around $100. I know the 205 is a stronger case, and there's a kit available now to swap in a 3:1 low-range gearset.

    Thanks,

    ~jp
     
  2. iwaxmyjimmy

    iwaxmyjimmy College web wheeler Premium Member

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    It uses a drive flange mounted to the rear output so a new drive shaft will have to be acquired. Also need an adapter to mate it to the 700R4, and I believe our (NP208) VSS is in the t-case and I'm not sure if there is a provision for one on the NP205 case.
     
  3. jonrpick

    jonrpick 3/4 ton status

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    What's the "VSS"?? What's the deal on the front driveshaft? Will it bolt up?

    ~jp
     
  4. iwaxmyjimmy

    iwaxmyjimmy College web wheeler Premium Member

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    vss= vehicle speed sensor front drive shaft should mount up. You will need out from behind a th400 trans for the 32 spline input shaft. I'm tryin to rack my brain to think of everything. Might want to search it to get all your info.
     
  5. sandawgk5

    sandawgk5 3/4 ton status

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    90/91 have electronic speedo and VSS in the tcase. The 208s from earlier have a normal cable and the VSS is an integral part of the speedo. Uses a light and a spinning mirror to get VSS pulse count. Goes into a green box behind the dash then into the computer. His should be a direct swap.

    What you need is a factory TH350-205 adapter, a 27 spline 205, and a spacer to account for the added length of the 700R4 output shaft. If you swap in the short shaft you may have issues with the front output hitting the transmission pan.

    With those three things the tcase will bolt right up to the transmission. Add shifters and new drivelines front and rear and you should be good to go. Your 208 speedo cable should be long enough to reach the 205 also.

    Ira
     
  6. iwaxmyjimmy

    iwaxmyjimmy College web wheeler Premium Member

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    Ok well I stand corrected on a bunch of things. Thanx for clearing that up sandawg.
    [​IMG]
    i so need one of these
     
  7. sandawgk5

    sandawgk5 3/4 ton status

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    {pushes button}

    "Well, That was easy!":D

    Ira
     
  8. iwaxmyjimmy

    iwaxmyjimmy College web wheeler Premium Member

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  9. blazindorito

    blazindorito 1/2 ton status

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    When you change the 208 to a 205 you have to cut the floor pan to make the shifter from the 205 work. I would recommend if you want to install the dual shifters on it to do it now that way you won't need to do it later, like I did. That thing is heavy. You will also need to modify your existing crossmember or get the crossmember from the donor truck to make the 205 fit.
     

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