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Changing Input Gears in a 203 rang box?

Discussion in 'The Garage' started by sled_dog, Dec 26, 2003.

  1. sled_dog

    sled_dog 1 ton status

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    Gonna look around for a 203, maybe a doublers not the worst thing, yeah its weight but hey I can deal. Anyway to find a 203 to go behind my 32 spline 465 will probably be a little difficult around here. So how hard would changing the input gear be so it could bolt up to my 465?
     
  2. Corey 78K5

    Corey 78K5 1 ton status

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    [ QUOTE ]
    GM SM465 4 speed Manual Transmission:
    If you have an SM465 transmission there are 3 ways to mate it to the NP203.

    1: Use a factory configuration. GM mated the NP203 to the SM465 in 1973-1975 using the 10 spline output in the 465, a 10 spline female input in the NP203 and a 4.25" adapter housing between the two. This configuration was used in a wide range of GM trucks but is somewhat rare. Problems are the 10 spline connection tends to wear in the long term and it's difficult to find. Positives would be the short length and the ability to use the common 10 spline output in the transmission.

    2: Use a SM465 that was originally mated to an NP208 transfer case. This 465 will have a 32 spline output shaft with a 8 3/8" adapter housing. You'll use a NP203 gearbox with a 32 spline input gear and the face of the 203 drilled and tapped with the GM round bolt pattern to match up to the factory 208 adapter housing. This works very well if you have the available length in the vehicle since the parts are commonly available and the 32 spline connection is very strong and durable.

    3. Use the factory SM465 to NP203 adapter housing with ORD's new 32 spline SM465 output shaft and a 32 spline input gear in the NP203. This allows the shortest overall length with the highest strength, most durable spline connection.



    [/ QUOTE ]
    I belive that #2 would be the way to go for You /forums/images/graemlins/thumb.gif

    Or You could be a cheap basterd like Myself and have a couple factory 465/203's setting around /forums/images/graemlins/wink.gif /forums/images/graemlins/tongue.gif /forums/images/graemlins/rotfl.gif
     
  3. sled_dog

    sled_dog 1 ton status

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    not so lucky, need to locate a TH400 203 with 32 spline input I guess.
     
  4. Corey 78K5

    Corey 78K5 1 ton status

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    Ok I'm a bit lost /forums/images/graemlins/confused.gif I assume that since Your ride is an 84 with a 32 spline 465 that it should have a 208 behind it. So all You should need is a 32 spline 203 from a th350 and to redrill the mounting plate and You should be good to go. Or am I the one who is not reading everything right /forums/images/graemlins/thinking.gif
     
  5. sled_dog

    sled_dog 1 ton status

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  6. R72K5

    R72K5 Banned

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    yeah if yhou find a 70s full time th400 truck then there you go, and th400 and 203 were commonly instaleld in a bunch of 70s K20 trucks, i believe it was the 32 short spline, long was 80s 465 i believe, and short 70s 465

    but... actually... i dont think 70s th400 203 shaft wil work for 70s 203 465, because in the 70s it was the 465 and 3 speed that were 10 bolt, haha

    so if youre wanting 70s 465 with a 203 then you need to find 10 spline

    and i dont think you can put an 80s 32 spline long from a 208 into a 70s 203 in order to use an 80s 465 haha


    good luck /forums/images/graemlins/laugh.gif
     
  7. Corey 78K5

    Corey 78K5 1 ton status

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    Opps My bad I was thinking that th350's were 32 spline /forums/images/graemlins/crazy.gif /forums/images/graemlins/tongue.gif
     
  8. R72K5

    R72K5 Banned

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    hahahahahaha!@ :P /forums/images/graemlins/rotfl.gif /forums/images/graemlins/thumb.gif
     

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