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th-350 to np-203

Discussion in 'The Garage' started by BigJ's K-Blaze, Mar 19, 2005.

  1. BigJ's K-Blaze

    BigJ's K-Blaze Registered Member

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    I finally have some money to get a tranny now but I dont know which one is going to fit. I have a 75 k-10 with a th350 and 203 now. The th350 case cracked im buying another trans. Im lookin for something thats going to be a bolt in job. Which trannys will work. Will a th350 that was mated to a 205 case work. If so, what years am I looking for. I found a trans out of a 81 k-10... but I dont know if that will work. Thanks for any help.

    -Justin
     
  2. BigJ's K-Blaze

    BigJ's K-Blaze Registered Member

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    Are the bolt patterns on the 205 and 203 cases the same? Or will it require an adapter to make them fit?
     
  3. diesel4me

    diesel4me 1 ton status Premium Member

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    Nope

    The 205 case uses an adapter that fits only the 205--the 203 one is different..

    A TH350 4x4 tranny is the same for all years,the adapter is what allows it to bolt up to different transfer cases..just about every case has its own specific adapter...:crazy:
     
  4. spoolnaround

    spoolnaround 1/2 ton status

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    You all ready have the adapter all you need is a TH350 that is a 4x4 version. The 2wd trannie wont work unless you change the output shaft. Any shop should be able to build you a trannie if all you need is a new case (use old internals minus clutches and bands), that is the most plentiful tranny in history. I have 2 in my garage.
     
  5. Mad-Dog

    Mad-Dog 1/2 ton status

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    That is a easy swap if you have 205 adapter housing, ORD makes a drive sleeve and bearing eliminator that you will want.​
    The ORD twin-stick is a nice addition as well.
    I acquired a '82 blazer and used the 205 it had for my K10:crazy:
     
  6. JK5

    JK5 1/2 ton status GMOTM Winner

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    First Gen GM trucks came with a 350/205 combos....
    73-75' and 80' had 350/205 combos also...80' was a slip yoke.

    I've used a couple 80' 350/205 combos...to replace my 350/203's.
     

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