The dreaded kickdown linkage

Transmissions and Rear Ends

  1. Bruceynz

    Bruceynz Well-Known Member

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    Hi Guys,

    Ok I have taken some measurements and drawn up them up for my setup, this seems quite a tricky thing to set up. So what I have to do to make it go right? any ideas?

    upload_2017-12-3_21-18-55.png

    kick_cable.jpg

    linkage1-jpg.jpg
     
    Last edited: Dec 3, 2017
  2. Aspen500

    Aspen500 Well-Known Member

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    You will also need a spring on the trans lever to pull it forward. Otherwise, the cable needs to be adjusted so the lever on the trans is in the full rearward position when the throttle is wide open.
     
  3. AJ/FormS

    AJ/FormS Well-Known Member

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    With the carb at WOT with all barrels wide open, you have to adjust the TV to max pressure, by pulling the lever all the way to the rear,as BUD says.
    If at part throttle, this now bang shifts too hard with that shift kit,or you don't like where the automatic upshifts are occuring, then you have to bring the carb pivot closer to the throttle shaft...... or reduce the line pressure. This will of course alter the automatic upshift speeds, so now you have to modify the governor pressure.
    So yes you are quite correct, it can be tricky.
    There is only one important adjustment; that the TV lever down at the trans, be all the way rearward at WOT. This is to maximize the holding pressure to the various clutches and servos inside. The more power you have, the more important this is.
    In your combo, I wouldn't be afraid to experiment with the line-pressure. With a shift kit already in it, I think with your 300ish hp, you will have a bit of leeway.
    You cannot adjust the line pressure without taking the pan off. To solve this, I drilled and tapped a small hole in the case,directly behind the adjustment screw,so I could insert an allen wrench there from the outside. This adjustment is very sensitive, so 1 turn is a lot. But during the initial set-up stage, 1 turn is about right. Install the access-plug-you won't be sorry.
    For higher automatic upshift speeds than the TV will give you, you need to cut some weight out of the governor. This too is a sensitive thing, it's easy to get carried away by taking too much off, and then under part throttle, the auto upshift speeds can get to be too high.
    To help your understanding;Here's the deal
    The line pressure is the first go-to.It sets all the basic pressures for normal driving.
    The TP (throttle-pressure,aka kickdown) increases the line pressure under full-power situations.and
    The governor fights them both to cause as early an upshift as possible. It does this by varying the pressure in accordance with driveshaft rpm. The faster the d/s spins, the more pressure it allows thru and the earlier the shift command. It's flippin ingenious.
    The TP is called the KD because it directly affects the upshift speed commanded by the governor, allowing you to vary the upshift-speeds with the foot-feeder. And yes, the kickdown speeds too,lol.

    Now, go drop the pan, find the adjuster for line-pressure, and make the access port.GO! It'll be the best hour you ever spend on that trans.
     
    Last edited: Dec 3, 2017
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  4. Bruceynz

    Bruceynz Well-Known Member

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    OK I have fitted a spring on the kickdown leaver, does the kd leaver have to go all the way back at WOT, I think its needs about an 1/8" more to go back hard?
     
  5. Bruceynz

    Bruceynz Well-Known Member

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    Just found this which is what I have been looking for on what way to adjust things, may help other people as well,

    Torqueflite Kickdown Adjustment | Moparts Question and Answer | Moparts Forums

    Here's the important part that everyone leaves out. Once you've adjusted/modified the Lokar linkage and lever for the correct arc travel distance as the throttle moves from idle to WOT, it's time to adjust the cable for proper main line pressure rise upon throttle opening.

    So, you've got the hole drilled in the lever. You've figured out the throttle bracket sweep distance and the correct detent lever sweep distance. Now, attach a pressure gauge to the line pressure port, second one back on the right.
    Moparts on the Web - Main Index
    Now, at hot idle adjust the cable so pressure rises, off base pressure, just as you tip into the throttle, in gear. Don't run yourself over.

    A cable too tight and it'll have a hard garage shift, late/rough upshifts, and an early passing gear down shift with a delayed upshift.

    A cable too loose and you'll get early upshifts, no passing gear downshift, and possible slipping that'll destroy the transmission.

    There is only one correct adjustment position for the cable and only one correct lever to throttle travel ratio. All other adjustments are done elsewhere on the transmission. Shift points are a function of the governor, and line pressure is properly adjusted on the valve body.


    Good luck
     
  6. AJ/FormS

    AJ/FormS Well-Known Member

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    If you do it that way, it might work;
    But if you have to take up too much slack, then the carb won't open all the way, and you'll have to re-engineer the position of the front pin. And that will require re-engineering the WOT TP again.


    On some other topics;
    Take care about how you put springs on your throttle shaft. Notice how on your carb, the springs are pulling the throttle-shaft towards the firewall.......as is the throttle cable. This is a sure way to prematurely wear out the baseplate and/or the shaft, cuz you are always pulling on that shaft. I like the springs to be installed like the factory did it with the spring pulling the cable toward the radiator in as straight a line as you can make it. This will ensure many years of trouble free service from the baseplate.

    I'm also not a fan of having the throttle cable attached up as high as you have yours. This makes a pipey engine a little easier to control, but it also takes more footfeeder travel to accomplish anything. I set mine up waaay closer to the throttle shaft, and bend the accelerator pedal arm to re-sync the WOT/Wot, or put a block under it so as not to overstress that T-shaft. I know this is a minor point, but it will help you set-up your front-mounted return-spring anchor.

    And when you get around to it, you might think about getting rid of as much rubber in your fuel-supply line as you can, and really it's also about the clamps. Gear-clamps have a nasty habit of coming loose. Well, actually it's the rubber that relaxes and squeezes out from under them. I use the factory type band clamps whenever I can, on account of they don't do that. You can reduce your gear-clamp tightening torque if you install two clamps per connection with the screw-heads rotated 180*. And try not to use the semi-transparent plastic filters nor the glass tube types. I highly recommend the metal canister throw-aways. In fact, I replaced all the rubber between the mechanical pump and the carb; and installed a very-large EFI filter in the rear close to the tank. It has over 125,000 miles on it and is still going.

    I'm only trying to be helpful, and to keep your car from catching fire.
     
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  7. Bruceynz

    Bruceynz Well-Known Member

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    Ok I have been under my car, I have checked it, at full throttle the trans leaver goes all the way back, at idle its just on the spring on the spool valve, I believe the free play in the trans leaver does nothing, its not unit you just hit the spool valve things start to happen, drunk to many beers tonight to road test, doesn't take much in NZ to be over the limit, 2 beers with dinner since it was 90F here today!
     
  8. AJ/FormS

    AJ/FormS Well-Known Member

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    That's right, the part that just waffles about freely is just freeplay
     
  9. BudW

    BudW Moderator Staff Member

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    Bruce, I just found this thread (been a bit behind on things, lately.
    I like your drawings and photos – for (IMO) they are helpful.

    The lever on transmission and carburetor are meant to be 1to1 ratio.
    That said, sometimes on the 3-piece setups, they don’t have room to make the bell cranks 1:1 – so the different holes are to compensate for that,

    Next. The location of cable attachment (both ends) and location of cable to lever points (both ends) also make a difference.

    See the cable attachment (in your picture, but modified) at point A and point B. It messes with a lot of the geometry of things when they are off.

    The transmission is where I see a possible issue (see red and yellow lines. I would “think” the cable attachment should be in line with the lower black line. Being it is at an angle, it appears to possibly be a geometry error (if that makes any sense.
    BruceAlmighty.JPG
    To give an idea on what I’m saying, I added “A” and “B” with cable attachment points (red circles) to top picture.

    I think in this case (without reading the web site), I would change the transmission lever cable point to the inner hole first, and retry it. I think that as well as maybe making a different transmission cable attachment point (tail housing) would make a world of difference).


    I love that idea!

    I’ve taken transmission pans down until I was literally red in the face (sic), to adjust line pressures – so I will start to do that on “modified” transmissions.
    BudW
     
  10. AJ/FormS

    AJ/FormS Well-Known Member

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    Well I just knew I'd be in and outta there a million times, so for me it was like getRdone. In the end I think it was only like three times. And about 2 tries to get the governor right. Now that's a PITA. But I couldn't see putting an access port in there as real doable for me,lol.
    I always try to picture how the factory testNtuned these things. I bet they, oh wait, I bet they didn't put many 4.30s in any cars, so maybe the TnT was pretty minimal. Still I'd like to see a 904 with a governor hatch. Or an external adjustable governor pressure regulator.Phew that's a mouthful!
     
  11. BudW

    BudW Moderator Staff Member

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    I have played with (and fixed) a bunch of governors in my time. I agree – not easy to get to.

    I suspect the factory played with them on dynos with the tail housings off (but what do I know).
    BudW
     
  12. 80mirada

    80mirada Well-Known Member

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    Chrysler used a transmission dyno, and had multiple transmissions setup to do testing on governor speeds. I worked with an engineer that was retired from the development center, and he had tons of pictures from the A-500/518 program
     
  13. AJ/FormS

    AJ/FormS Well-Known Member

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    You know what tho, I was thinking. You could unhook the TV off the carb, and take it for a gentle ride, and see if the auto-downshifts are still clonky. Then tie or wire the trans lever about half way back, or quarter way back, and see if it's still the same clonky. That could tell us a little about the governor pressure, I would think.
    Then again I guess you could just put a pressure gauge on it.With a really long hose,lol.
     
  14. Bruceynz

    Bruceynz Well-Known Member

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    Hi Bud,

    Lets call the leaver on the trans KD for quickness

    Can not alter the mount for the cables on the tail housing one bit, if I do they will hit the body of the car, so that rules this out. If I change to the smaller hole on KD I will then be opening the throttle and the KD leaver will be moving further, won't this in turn make it harder for the governor to build up pressure then as the KD will be back further and leave it stuck in second??

    I see what you are saying, you are trying to get the distance from the pivot on the carb to the same as the trans. this is all good assuming the trans leaver movers the same distance as the throttle takes to open the butterflies.

    If I change to the hole closer in the KD leaver will be all the way back before the throttle is all the way open.

    Hmmmmm Hope my garble makes sense, put me on the right track if I am wrong.
     
  15. AJ/FormS

    AJ/FormS Well-Known Member

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    I worked in a driveline shop for over 5 long years. They had one of those transmission dynos, powered by a 302Ford. Every single auto they built went onto the dyno, and one old guy adjusting the pressures.
    I was on the other line. We did manual trans, differentials, and I eventually moved on to powershifts.
    That dyno guy was just a couple of car lengths away, and that old guy just hammered the tranny out all day long.
    Old is relative. at the time I wasn't quite 30 yet, and I bet he mightbin just into his 50s lol. Now,roughly 40 years later I'm the old guy.
     
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  16. Bruceynz

    Bruceynz Well-Known Member

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    This is a nightmare to be honest, seems that not many people have gone down this road with their trans, I am in a bit of a tricky place cause I can't get rods and stuff from other cars to play with, I am stuck with what I have got, I did see though that you can get a Bouchillon setup, this setup comes with a bracket that bolts on the carb and the leaver for the trans at the right length and you clip all together job done.

    Resources: Kickdown Cable Installation Instructions - Bouchillon Performance Engineering
     
  17. Bruceynz

    Bruceynz Well-Known Member

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    Yeah your the old guy but pretty dam knowledgeable!!!! I like how you work out all the speeds and cylinder pressures for me! From that you always tell me to change my rear end ratio :)

     
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  18. AJ/FormS

    AJ/FormS Well-Known Member

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    I think your fighting this from the wrong end. You may have to go into the governor and change it's calibration, and then re-sync the KD.
    But it may just be that the TV spring is too stiff and or the minimum TV travel is too tight. Your KD adjustment should not be this tricky to adjust; it's supposed to be just the fine tune to the system.That is why I asked if you still had the instructions for the shift kit. Many times the installer will write in the actual installed tips.He may have installed it for a different application.

    Does it bang-shift pretty hard,maybe chirping the tires on the shifts
     
  19. Bruceynz

    Bruceynz Well-Known Member

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    Sorry I have no idea, he tells me over the years he has installed a lot of transgo kits.
     
  20. AJ/FormS

    AJ/FormS Well-Known Member

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    Well that's too bad. There are multiple ways to install those. I have done a few maybe 8 or 10. We used to sell those And I put one in every car I owned back then. Plus a few for friends, you know how it goes.

    How about those bang shifts?
    and I forgot what rear gears you're running?