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TRANNY QUESTION

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Robbyj56, May 17, 2002.

  1. Robbyj56

    Robbyj56 Registered Member

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    i didnt get much feedback the first time so im posting it again. /forums/images/icons/smile.gif ive got the original 1983 tranny... I havnt looked into which model. until today the tranny has been working flawlessly. we just spent hella cash on a new motor. yesterday was my first day driving it since i got it back, the tranny was fine all yesterday and the majority of today, but on the way home it was stuck in what i think is first gear... and after experimenting, it would shift to what i think is 2nd at around 44 mph. i took it up to 70, going downhill, and it would not shift another gear. I am short on money as it is, since i just spent thousands on the truck, this is scaring me. i had also been testing out 4 wheel Lo right before it happened, not any serious offroad, just a small patch of grass near my house, i didnt put the truck under any stress. if yall have any other idea what might be causing it please reply!
     
  2. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    If its a TH400, make sure the vaccuum is correcly connected to the modulator... and check the fluid. That can have everything to do with it. Good luck, and get the trans identified if you want real help!

    -Dan
     
  3. Robbyj56

    Robbyj56 Registered Member

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    how would you go about identifying which tranny you have? it is a 1983 4 speed automatic, fitted with a 305 engine from the factory. is there a common tranny that was installed with those stats?
     
  4. seslick77

    seslick77 1/2 ton status

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    Sounds like you might have the ole 700R4. Look at the tranny pan. I f its square its a 700, if its square with a notch taken out of one corner its a TH350 (kinda looks like Kansas), if its got alot of turns and bends its a TH400. Also if you look at your shift indicator, if it has 1,2,3 D or 1,2,D then D with a box its a 700R4. If you look on the net you could probly find pics. Or try an LMC catalog, it has a page on tranny ID. /forums/images/icons/smile.gif
     
  5. Robbyj56

    Robbyj56 Registered Member

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    i checked out my tranny pan... it is a square with a notch cut out of the rear driver side. so according to what you say that would be a TH350, but... the shifter has 1 2 3 D, which is characteristic of a 700r4, although it only goes down to 2... not all the way to 1, so tell me your opinion on that one. i just ordered an LMC catolog. and just out of curiosity... which transmission is the best?
     
  6. NITRO

    NITRO 1/2 ton status

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    that would mean ur truck had a 700 originally and has been swapped for a th350

    NITRO
     
  7. Robbyj56

    Robbyj56 Registered Member

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    the guy we bought the truck from told us it was the original transmission... but he also told us it had a 350 when it only had a 305.
     
  8. 4x4_76

    4x4_76 1/2 ton status

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    I have same problem on my K5.First it worked fine,but then,little by little,it started to have malfunctions.I also have TH-350,and it may have shift-kit installed.Could it be possible that modulator is stuck?Vacuum pump is working ok.
     
  9. 89Blazin

    89Blazin 1/2 ton status

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    The place to start is replace the vacumn modulator. You might see if you can manually shift up through the gears Also inspect the color of the tranny fluid.
     

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