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stupid transmission

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by TorkDSR, Jan 14, 2002.

  1. TorkDSR

    TorkDSR 1/2 ton status

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    im having serious issues with my *new* trans. i just put the 700 into my truck (79 k15, np205) and it wont shift right at all.
    are there any thoughts on this. ive messed with the $#@%$%^#%^%^#%^%& TV cable 90 bazillion times, i got the pressure gauge and everything, but im having some issues.
    Help please

    beligerence doesn't justify intelligence.
    <font color=blue>wheelers hate posers.</font color=blue>
    <font color=red>79k15/400/700r4/205/38.5</font color=red>
     
  2. Blue85

    Blue85 Troll Premium Member

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    What does it do wrong and what does it do right?

    <font color=green>Today's Forecast: Partly cloudy with a chance of mud</font color=green>
     
  3. TorkDSR

    TorkDSR 1/2 ton status

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    seems real sloppy in the shifting, doesnt downshift when i need to accelerate, or when pulling a hill. and just before it shifts it revs a couple hundred rpms then tries to go into gear, but every thing is so mushy.

    beligerence doesn't justify intelligence.
    <font color=blue>wheelers hate posers.</font color=blue>
    <font color=red>79k15/400/700r4/205/38.5</font color=red>
     
  4. KrebsATM02

    KrebsATM02 1/2 ton status

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    I'm having those same problems, but my tranny is a year and a half old!! Someone tell us what is out of adjustment. - Doug


    Doug Krebs
     
  5. TorkDSR

    TorkDSR 1/2 ton status

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    i have my throttle valve linkage set (TV made easy.com) and its still all weird




    beligerence doesn't justify intelligence.
    <font color=blue>wheelers hate posers.</font color=blue>
    <font color=red>79k15/400/700r4/205/38.5</font color=red>
     
  6. Big_B_Murphy

    Big_B_Murphy 1/2 ton status

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    That sounds like what mine did just before it blew up. It also did not seem to want to shift back into 1st when I came to a stop. The thing had supposedly been rebuilt 3 months before. Upon further inspection I found that only one of the two vacuum lines that go to the modules on the firewall that are wired to the tranny was connected. I don't know for sure if that was my problem, but I do know that I am not going to put a th700 POS back into my K5. Hoping to go with a sm465, if not then a th350 or th400.

    <font color=red> It is just as much fun to build it as it is to bash it</font color=red>
     
  7. DMK

    DMK 1/2 ton status

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    There are no vaccum conections on a 700r4.
     
  8. Big_B_Murphy

    Big_B_Murphy 1/2 ton status

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    It is not a vaccum connection to the th700. The wiring harness from my th700 goes to two modules on the firewall. each of those modules has a vacuum hose going to a manifold vacuum. At least this is how my 85K5 was.

    <font color=red> It is just as much fun to build it as it is to bash it</font color=red>
     
  9. Blue85

    Blue85 Troll Premium Member

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    One of them is an input and one is an output. The input one is toward the driver's side and it uses (ported) manifold vacuum to control the torque converter lockup. The output one uses the electrical signal from the tranny to allow the EGR valve to work only while cruising.

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  10. Blue85

    Blue85 Troll Premium Member

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    When it revs up before going in to gear, is that just on the 2-3 shift or does it do it when you initially put it in drive?

    Was a "shift improver" kit installed?

    Was the servo upgraded or did it stay stock?

    Do the shifts happen at about the right rpm or are they always too high or too low?

    Did the 700/205 combo ever come from the factory or did someone rebuild this tranny with a new output shaft?

    Sometimes setting up the TV by the book doesn't get it exactly right. It may help to move the adjuster on the throttle linkage in or out a click or two to see if it improves the shifting characteristics.

    It sounds like your TV might be set too loose and the tranny thinks that you are always on the gas really light. This could spell disaster for the tranny before too long.

    If your line pressure is measuring all right, then it could also be the TV valve train, TV limit valve, MTV up or MTV down valves. It only takes one sticky valve to mess everything up (don't ask me about all of experiences that prove this [​IMG]).

    <font color=green>Today's Forecast: Partly cloudy with a chance of mud</font color=green>
     
  11. TorkDSR

    TorkDSR 1/2 ton status

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    not to be a smart a$$ but if i answer all those questions will you be able to solve my problem[​IMG]
    sometimes itrevs btw 1,2,and2,3
    no shift kit (yet)
    stock servos sometimes the shifts happen really late so im tached a little high
    the 205/700 was never a factory option. but someone very knowledgable rebuilt the trans
    and the tv has been adjusted infinitly

    beligerence doesn't justify intelligence.
    <font color=blue>wheelers hate posers.</font color=blue>
    <font color=red>79k15/400/700r4/205/38.5</font color=red>
     
  12. Blue85

    Blue85 Troll Premium Member

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    Well, if you don't think that we can help solve your problem, why are you asking about it? And how can anyone help you at all without any information?

    To shift from 1st to 2nd, all the transmission does is apply the 2-4 band. To get it to rev up between 1st and second means that the low/reverse clutch is letting go and then grabbing again, unless it is going right to 3rd gear from first by applying the 3-4 clutch.

    I think that you should ask the guy who rebuilt it what is wrong. He should have the best chance of diagnosing the problem.

    <font color=green>Today's Forecast: Partly cloudy with a chance of mud</font color=green>
     
  13. TorkDSR

    TorkDSR 1/2 ton status

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    i didnt mean to be snotty about it, i felt like i was being interrogated,sorry.
    the guy didnt really rebuild it, he just tore it down, dropped in the new output shaft and put 2 or three seals in it, but ill give him a call, thanks for the opinion


    beligerence doesn't justify intelligence.
    <font color=blue>wheelers hate posers.</font color=blue>
    <font color=red>79k15/400/700r4/205/38.5</font color=red>
     

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