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Th350 help!

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by Shadow25!, Jan 29, 2003.

  1. Shadow25!

    Shadow25! Registered Member

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    Ok.. I have a 72 blazer which I decided to pull the th350 and rebuild due to poor shifts (my first rebuild). So heres my question.. The vavle body in my trucks tranny is different than the valve body out of my 70 Nova.. The underside of the valve body on the nova is completely solid while the truck trannys Valve body underside looks like its been shaved with little steel balls stuck into the holes. The valve bodies have the same casting numbers, but the one out of the truck tranny has a big C cast in it after the numbers. Someone told me this means its a lock-up th350C tranny, but there were no electrical conectors on the case..It is beginning to look like the tranny is not the original, as the codes are no where to be found on the case. So my questions are:
    1. What is the difference in the valve bodies?
    2. Is there any way it can be a th350C without electrical connectors?
    3. If it is a th350c will a non-lockup torque converter work?
    CM001@aol.com
    Any other suggestions are welcome, and thanks!!
     
  2. 72beater

    72beater 1/2 ton status

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    According to Ron Sessions in "turbo hydramatic 350 handbook" (HPBooks), the 350C HAS electrical connectors and no band adjusting screws nor ribbed oil pan. Also, the reason that you have no number MAY be that the model id number was stamped in the oem oil on the right vertical side, so that if you have an aftermarket pan, then the number would obviously be lost. (and that is the number that tells the entire story). (you might also check the governeor cover). I'm not sure I can asnswer your question directly, but I do know that the lockup, when engaged, just locked the clutch in the converter. So if you never applied a signal to the lockup connector, it would not matter what kind of torque converter you used. As for the C on the valve body, it might mean lockup VALVE BODY. I can't find anything on that. Do you have a picture of it? If so, post it or send it to me. Hope this rambling helps. /forums/images/graemlins/confused.gif
     
  3. bouncytruck

    bouncytruck 1/2 ton status

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    I rebuilt my TH350 last summer. From your description, mine is similar to yours. I believe that my tranny was out of a '73 or '75, as is my NP203 t-case. Mine is not a lock up though. When I rebuilt mine, I used two books, the one described by 72beater and the Haynes Turbohydromatic rebuild book. When I didn't understand the description or the photo wasn't clear in one, usually the other one had a good description.

    I posted a few photos from my rebuild at http://info.imageink.com/chris/tranny.htm

    One of the board members took extensive photos of his TH 400 rebuild - http://groups.msn.com/Ryans1972Blazer/th400transmissionrebuild.msnw?Page=1&pgmarket=en-us
     
  4. Shadow25!

    Shadow25! Registered Member

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    Yeah, I have a feeling the valve body is just out of a different tranny.. from what I gather they are interchangable... Anyhow Ill check out those other references you gave me.. Thanks alot for both of your posts, you've both been very helpful.. /forums/images/graemlins/k5.gif
     

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