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Will a NP203 from a TH350 Bolt on to a 700R4?

Discussion in 'The Garage' started by Grim-Reaper, Nov 5, 2002.

  1. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Is the output the same? I know the TH350 is 27 splines and sticks out about 1 inch past the housing with the adaptor off. What I don't is if that's the same as a 700R4 and if the bolt pattern for the 700 to adaptor is the same as a TH350 to Adaptor.
     
  2. yunit

    yunit 1/2 ton status

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    You will need to change the output shaft on the 700R4 and use the 203 adaptor.
     
  3. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    OK that is what I was afraid of. I was thinking the 700 stuck out like 2 inches.
     
  4. u2slow

    u2slow 1/2 ton status

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    Might be able to cut the shaft down without tearing down the tranny.

    I had a TH350 at one time where the shaft had obviously been chopped to fit a 4x4 application. Still have the shaft!

    Do some measuring and see what's possible. You might be able to save yourself some time/$$$.
     
  5. jeffro

    jeffro 1/2 ton status

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    I've seen a space to place between the transmission and t-case.
     
  6. or2play

    or2play 1/2 ton status

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    Don't cut the output shaft. The more thats cut off the end of the shaft is that much less of a splined connection between the tranny and tcase. I'd get the output shaft conversion. 160 bucks and tear down the tranny. Done. If you don't want to tear the tranny down, advance adapters make a spacer that goes between the tranny and the 350/203 adapter. Can't recall price on that at the moment.
     
  7. thebigdaddyof2

    thebigdaddyof2 1/2 ton status

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    Hey Grim,
    From the info I gather from SW, you can use the 700R4/NP208(or NP241) adaptor, and a T350 version NP203. Just mate the cases together and redrill the holes in the 203 to match the adaptor. Stephen does stress that if a doubler is planned, to wait till you receive the doubler so you can clock everything to the right position before drilling. I'm sure this was covered in the ORD forum somewhere.
     
  8. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Well I would rather put a shorter shaft in the tranny then add any more lenght to my drive line. 700 is two inches longer than TH350. Well I can use 2 inches but I can't use 4. I have a set of Zero rates in the rear and did plan to move the rear back about 1 inch. With a 700 I would be able to retain my stock rear drive shaft. I'm trying to avoid having to retube both drive shafts and if possible I would prefure to run a stock rear so that if I ever bust one a replacement is as close as the nearest junkyard.
    Now I know for a fact that GM had soemthing that worked in the early 80's. When the 208 came out people were busting them and GM was installing 205's on the back of 700's.
    The other issue is the shifter. THe shifter bolts onto the transfer case adaptor on a 203. I have about 2 inches of tunnel I can cut but after that I'm into floor.
    It's all a game of inches /forums/images/graemlins/smile.gif
     
  9. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    </font><blockquote><font class="small">In reply to:</font><hr />
    I'd get the output shaft conversion. 160 bucks and tear down the tranny.

    [/ QUOTE ]
    Have you got a part number and supplier for the shaft?
     
  10. or2play

    or2play 1/2 ton status

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    Don't have a part number. You can get it from offroad design. Give them a call.
     
  11. u2slow

    u2slow 1/2 ton status

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    Dunno how a cut-down shaft would have less spline engagement /forums/images/graemlins/confused.gif

    The t-case can only go on until the splined potion of the male shaft ends - no further. And you only need to cut enough off to make the tranny and t-case meet.

    The deciding factor on whether a cut-down shaft is feasible, is if the output shaft is splined far enough back into the tranny.
     
  12. or2play

    or2play 1/2 ton status

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    well a turbo 350 output shaft sticks about about 7/8s of an inch. A 700r4 output shaft sticks out about 2 inches. If you cut it down to fit a 203 case with a 350/203 adapter ( which is one inch thick) your leaving little to no splined area on the shaft. IF you were able to get it to fit together, from what I've seen in my experiance says its asking for lots of troubles down the road.
     
  13. Chris_T

    Chris_T 1/2 ton status

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    I think you're right to go with the adaptor shaft. I have no direct experience, but have heard stories about guys making a spacer and ending up with driveline vibration issues, something to do with the amount of shaft engaging. (That's not to say it won't work, for all those have been able to do so) I'm sure the craftsmanship of the spacer has a lot to do with those stories. I'm not 100% sure if it is the shaft you're looking for, but I have one from Advance Adaptors in my 700R4 that allows me to use my adaptor and 205 that was initially behind a TH350. Stands to reason the same shaft will work with a 203. Sorry, but no part number. FWIW I've had no problems at all with the shorter shaft with my 205 and no driveline issues with it.
     

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