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    th350 adjustment help

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    HeavyChevy77
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    th350 adjustment help

    Post  HeavyChevy77 on Tue Jan 27, 2015 8:14 pm

    I put a 1" spacer on my qjet to help with my fuel percolation problem
    I had to disconnect the kickdown cable on the driver side rear on the intake manifold bracket. The angle and length to the carb throttle arm has changed because of the spacer, now it angles upward.
    I've tried setting it by
    -releasing the tab on the cable
    -going wot holding i
    -seat the slotted end on the carb arm to make the cable short as possible
    -push the tab down
    -release the wot
    Am I doing something wrong. It feels fairly loose.
    Do I need a bracket to make em even level
    Suck to drive in the city doesn't shit till you get up to 4000
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    solo79
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    Re: th350 adjustment help

    Post  solo79 on Tue Jan 27, 2015 8:41 pm

    There is a bracket you can get, I think Holley makes it.  You can also fashion your own, all you really need to to do is drop the mounting point down where it used to be and connect the kick-down back up.  The thing I'm wondering though, you said it's not shifting right?  The kick-down on a TH350 can be completely unhooked and the transmission will still shift normally, you just can't punch it and downshift.  If you're not shifting until high rpm, I'd be looking into the vacuum modulator or the hose/line at the carb.  If that gets disconnected, or the modulator goes bad, they will behave that way. I've never had one not shift normally due to the kick down not functioning or being unhooked. Now, if you have the cable suspended all of the way out somehow, then it may hold you in 2nd gear. Try unhooking it completely and drive the car and see if it still won't shift.


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    Re: th350 adjustment help

    Post  HeavyChevy77 on Tue Jan 27, 2015 8:47 pm

    By dropping the mounting point u mean everything at the same height right?
    It shifts but all late and didn't do it before I put the spacer, tho sometimes it would lag on the freeway but it the city it'd shift on time and like butter.
    I have a modulator and fluid and gasket/filter ready and thought about doing that.
    If I step on it  it'll drop a gear so the revs would be high.
    Also I was messing with the idle mixture screws while I was doing all that stuff too.
    And it would hold 1st for a while the shift when I let off the pedal.
    The cable slot is on the middle of the left side of the carb and slopes towards the back left side


    Last edited by HeavyChevy77 on Tue Jan 27, 2015 8:53 pm; edited 1 time in total
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    Re: th350 adjustment help

    Post  solo79 on Tue Jan 27, 2015 8:52 pm

    HeavyChevy77 wrote:By dropping the mounting point u mean everything at the same height right?
    It shifts but all late and didn't do it before I put the spacer, tho sometimes it would lag on the freeway but it the city it'd shift on time and like butter.
    I have a modulator and fluid and gasket/filter ready and thought about doing that.
    If I step on it  it'll drop a gear so the revs would be high.
    Also I was messing with the idle mixture screws while I was doing all that stuff too.

    Yea, I had a spacer once, I just cut/fashioned a piece of steel which I bolted to the original linkage, then drilled a hole where I wanted it and put the kick down "fastener" in it so that it was level again when hooked up. However, you can have some play there, it doesn't have to be perfectly level. My current setup in my 82 Trans Am with TH350, the cable is actually "looped" a little and works "most" of the time. I still haven't remedied it yet.

    I'm wondering if the linkage in your transmission where the cable connects might be stuck in "kick-down" position which would cause problems. If not, I'm betting it's the modulator. Try unhooking the kick down completely and push and pull on the cable to see if it's operating. You'll hear the linkage move in the transmission when you do this. Engine off of course. If the cable is operating correctly, leave it unhooked and drive the car. If it still shifts high rpm only, it's most likely the modulator or the line/hose attached.


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    Re: th350 adjustment help

    Post  HeavyChevy77 on Tue Jan 27, 2015 8:56 pm

    Thanx solo79 would I release the tab when I push and pull on it
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    Re: th350 adjustment help

    Post  solo79 on Tue Jan 27, 2015 8:59 pm

    HeavyChevy77 wrote:Thanx solo79 would I release the tab when I push and pull on it

    No, you should be able to just pull on the metal loop end of the cable and feel it pull out and push it back in without pressing the top tab. Similar to how the carb linkage would move it.


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    Re: th350 adjustment help

    Post  GM B-Body Forum on Tue Jan 27, 2015 10:49 pm

    I leave mine disconnected and when i get a chance to drop the pan and change the filter im going to unhook it and plug the hole. As far as erratic shifting goes, thats all in the modulator, mines still the original one and works great, just have to make sure the vacuum line is good and not leaking, if that modulator doesnt get any vacuum it will only shift in WOT so at like 4000 rpm. But if you want to use the detent cable, the way to "adjust" is the same way you would with a TV cable on a 700r4 or 2004r. Pull the cable all the way out, then open the throttle all the way, technically they should both be even when at WOT. When i had mine connected it was loose like maybe a 1/4 to 1/2" of movement when the metal end was on the bracket when it was in idle, but at WOT it was just perfect. I ran a holley carb with a 1 inch spacer but i used the bracket which relocates the throttle cable and kick down cable.


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    Re: th350 adjustment help

    Post  HeavyChevy77 on Wed Jan 28, 2015 1:09 am

    Where is the modulator . Isn't it on the rear of the pan on the passanger side? And has a clamp like a dizzy right? Ima try u hooking it take it for a spin if it still acts up ill do a fluid change and modulator replacement.
    Also sometimes when its in 2nd it might shift to3rd around 2500rpm depending how hard in stepping on the pedal.
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    Re: th350 adjustment help

    Post  solo79 on Wed Jan 28, 2015 6:22 pm

    HeavyChevy77 wrote:Where is the modulator . Isn't it on the rear of the pan on the passanger side? And has a clamp like a dizzy right? Ima try u hooking it take it for a spin if it still acts up ill do a fluid change and modulator replacement.
    Also sometimes when its in 2nd it might shift to3rd around 2500rpm depending how hard in stepping on the pedal.

    Yea, the modulator is on the passenger side above the back of the pan. I think there's like one small bolt holding a little clamp on it if I recall correctly. Be sure and inspect the rubber hoses at each end of your steel modulator line too. Even a slight crack will cause trouble. Keep us posted!


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    Re: th350 adjustment help

    Post  HeavyChevy77 on Thu Jan 29, 2015 3:32 pm

    Hey guys I havent been able to do a fluid change yet since in in my auto classes planned for Saturday or Friday if I finish my moms car early
    I was looking at the book procedure and says for the adjustment as
    -release tab on the cable
    -release the cable assembly from the intake bracket
    -place carb lever it in WOT
    But on qjet DISENGAGE secondary lock-out BEFORE placing lever in WOT
    (What does this mean my knowledge on qjets is minimal, book just says how to adjust the lockout)
    - Close tab and release WOT
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    Re: th350 adjustment help

    Post  HeavyChevy77 on Thu Jan 29, 2015 9:11 pm

    I fixed the shifting problem
    Now its lags just a touch maybe cause of old fluid or because it was getting used to shifting till it peaked
    Gonna change the fluid over the weekend
    This is what I did
    -release tab
    -remove the tab housing from bracket
    -close secondarys
    -wot close tab then plug to bracket realease WOT
    -Done
    Now I see 2nd cursing at 30mph

      Current date/time is Thu Apr 27, 2017 4:33 pm