904 Kickdown - Semi early shifts no more kick-down ?

Transmissions and Rear Ends

  1. 8v-of-fury

    8v-of-fury Well-Known Member

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    Not sure why I haven't any part throttle kickdown at any time. The car is now a 4bbl thermoquad and the kickdown has been moved back on the intake and modified to suit.

    So at idle, the kickdown lever is fully towards the firewall and seated against the stop at the trans. It is held forward via a spring, and moves freely with the throttle or by hand.

    The car will shift ok, but never gives a part throttle (or full throttle kickdown for that matter) ever. Not even if you floor it right after it has shifted to second gear and want it to drop back down to first gear.

    Perhaps I need some tuning done at the trans end? What can be done to raise the shifts points and get the kickdown back?
     
  2. Aspen500

    Aspen500 Well-Known Member

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    With the throttle wide open, you need the throttle valve lever (a.k.a. "kickdown" lever) on the trans to be at it's rear stop also.
    This is a very important adjustment. It doesn't only control the part throttle downshift, it also controls the line pressure, which controls shift points. Higher pressure = higher shift points. If misadjusted it will also cause premature transmission wear.
    Another way to increase shift points (and firm up the shifts somewhat) is to adjust the pressure relief on the main control body (valve body). You have to be careful though, as the pressure is increased, the shift points will be higher BUT you may hit redline before it shifts at WOT. Not a problem if you pay attention and let up on the throttle a bit and let it shift.
     
  3. 8v-of-fury

    8v-of-fury Well-Known Member

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    The trans rod is going fully towards the firewall, so I am not sure it is out of adjustment. It shifts just fine, and has for the last 2 years. Minus the no kickdown basically. Hypothetically, go with me here, If the car never sees WOT does the fact that the arm doesn't reach its full stop matter? Or does the rod meeting its full stop set the adjustment for the rest of the rods movement?

    The reason I ask, is because it is a slow car and at no time does pushing the pedal to the floor do anything more than say 1/2 or 5/8 throttle would accomplish. Except for maybe wasting more fuel ;)
     
  4. 8v-of-fury

    8v-of-fury Well-Known Member

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    This seems pretty intersting to me really, as I feel the stock shift points are WAYYYYY overrated. They are so low, it continuously bogs the engine down where there is no power. BUT, I guess the shifts should hold out a bit longer in proper operation when you hold the pedal down more than 1/8th pedal.

    That's the beauty thing though with this, you can do normal traffic speeds and get to speed with no more than a slight touch on teh pedal. The throttle plates are barely open at that point. I love it hah
     
  5. BudW

    BudW Moderator Staff Member

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    I’m not sure what you are describing here. Can you re-phrase it, please?

    I “think” you are saying the kickdown linkage is in full back position, all of the time, maybe?
     
  6. Aspen500

    Aspen500 Well-Known Member

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    The factory shift points are made for comfort, the average driver and for the best fuel economy whether it was built in 1976 or 2016. I'm talking your typical, average, everyday vehicles. There are exceptions such as high performance models for example. Those are built for a different type of driver and personally, I think they shift the best. Drive some of the newer cars once. Those darn things are in 5th or 6th gear by the time your doing 30 mph on light accel.

    My way around it, even when driving the '96 Dakota,,,,,,,,,,,,,,,,,,,,,,shift it manually. Unless you cancel O/D, it will go to O/D and lock the converter clutch at 35 mph and as you said,,,,,,major lug. Of course, driving at 35 mph in O/D on anything but perfectly level road (does not exist around here pretty much) it'll be in and out of O/D constantly and the TCC will lock, unlock, lock, unlock at the slightest throttle increase. Annoying as all hell. Anyways,,,,,,,,,,,,sorry for going off on a tangent:D
     
  7. BudW

    BudW Moderator Staff Member

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    I don’t mind automatics – but they are just not the same as driving a car with a manual transmission.

    All FMJ cars with automatics (904 family or 727) uses a hydraulic computer to do its shifting.
    The valve body where the battle of fluid line pressure, vs spring pressure and vs centripetal force (spring vs weights (ie speed)) takes place. Changing one of the 3 items effects everything else. Yes, Chrysler (and other manufactures) like them for a smooth comfortable ride while reaching emissions and/or fuel economy goals, as well.
    Performance and ease of adjustability wasn’t really factored into it, much.

    When it all comes down to shift points and/or shifting manually – then why not go manual and just be done with it? (yes, I know, easier said than done).
    My two cents worth of opinion.

    Side note: the list of cars I’ve owned are located at First time entering into a Car Show .
    The only ones which I owned with manual transmissions were the ’87 Daytona Shelby, the 92 Shadow America and ’97 Dodge ¾ ton diesel pickup (still have). 3 out of 17 vehicles – and probably the three vehicles I’ve had/have the most fun driving (well the ¾ ton pickup is not as fun in town. It is meant to be carrying or pulling something. The ride empty is, um, hard on the kidneys).

    That said I drove all three manual vehicles for more miles than others – which exception of wife’s minivan(s) – which we take as a family – not solo. I have put almost 200k miles on the pickup, for example.

    Will I drive or own an automatic – yes.
    Do I prefer it – NO.
     
  8. Aspen500

    Aspen500 Well-Known Member

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    I don't mind a manual but prefer an automatic for daily drivers. Worst time I ever had was in the NW suburbs of Chicago at Audi school (when I was dumb enough to be an Audi dealer tech). My dealer sent me down there in a 2007 Jetta 2.5 with a manual trans. In stop and go, more stop than go,,,,,,,,, traffic like that, IT SUCKED, big time.
    The only manual cars I've owned were my first car at 17 yrs old in 1981, a 1970 Barracuda Gran Coupe 4-speed, a '66 Dart 2dr sedan with a three-on-the-tree, a '66 Dart GT 273 4V with a 4-speed and a 1978 Toyota Celica Supra GT with a 5-speed. Shut up, I KNOW. I needed a car and it was the only decent one I could afford to buy at that exact moment. It was either the Toyota or walk. Every other car or truck was an automatic. Wait a second,,,,,,,,,,my Aspen was a 4-speed O/D originally, kind of spaced on that, lol. Oh yeah, also had a '65 Sport Fury ragtop that was a 4-speed. Guess I've had more manual trans cars than I thought.:confused:
     
    Last edited: Sep 24, 2016
  9. Bruceynz

    Bruceynz Well-Known Member

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    I have gone from 318 2bbl to 360 4bbl and I have reached the conclusion that the only way is to manually shift it, I take my 360 to 5500rpm all I can get out of it in auto mode is 1 2 shift at 3800rpm, got it up from 3000ish by playing with linkage, just have to face it that a stock trans is not calibrated for performance. For city driving trans is fine, not taking it to 3800 for 1 2 shift just grand ma driving it, just can't go fast in city.
     
    Last edited: Sep 24, 2016
  10. Dr Lebaron

    Dr Lebaron Well-Known Member

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    Q-is it a real Mopar 4bbl linkage or something put together?
     
  11. 8v-of-fury

    8v-of-fury Well-Known Member

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    No sir, the rod is fully towards the radiator when the car is at idle. There is a spring that holds it frontwards, as I've read there should be. When the throttle is applied the rod will go with the throttle fully and all the way back to the firewall.

    Yup, I drive a '13 Mustang too with the 6spd auto. Difference being, that engine has almost 400 lb-ft of torque which is can manipulate with its VVT. The M-body, not so much. Also if you punch it whilst idling along in 6th gear, it will drop and wind the hell out of 3rd gear for you too so its all good.

    Sadly the 904 has no cancellation for lockup :( so that doesn't work for me, it will lock at 60km/h regardless of throttle position.

    Yeah, I'll do that when I drop a 440 in it lololol.

    I'm sure it would be fine if it worked properly, no kick-down is horrible. It won't down shift to gain speed it just lugs 3rd (At any speed) and will suffer until you reach a better speed.. If you need to slow in 3rd for like someone in front of you, but then go to get back up to speed you can feel the engine being a dog and getting shittered by the carb cause you've opened the throttle to far and it can't get the engine ot react.

    It is a modified stock 2bbl piece. I had to move the mount back a set of intake bolts so it would clear the thermoquad, and then I lengthened the arm where it connects to the throttle. It does seem to be working properly though!
     
  12. BudW

    BudW Moderator Staff Member

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    The Thermoquad is a wide carburetor. What Chrysler did was move the rear intake bracket outwards (same position towards rear of car, but closer to L/F Wheel) so the bracket is practically on top the valve cover.

    BudW
     
  13. 8v-of-fury

    8v-of-fury Well-Known Member

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    How does one do this?
     
  14. 8v-of-fury

    8v-of-fury Well-Known Member

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    Do your guys' M-body 904's have a part throttle kickdown? I swear this car had one years ago when it was all stock... Like a small amount of pedal allowed a smooth down shfit.
     
  15. BudW

    BudW Moderator Staff Member

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    This requires dropping the transmission pan down and adjusting the valve body.
    For some people, this is not for the weak of heart (it’s messy, and sometimes requires one to do it several times to get it right).

    With a 2.2 gear ratio, these cars DEMAND a part throttle kickdown.
    I suspect your linkage is out of adjustment.

    BudW
     
  16. Miradaman

    Miradaman Active Member

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    Write to Mopar Action on their website. They had an article on making your own shift kit for 904 Torqueflite. You have to drill out so.e holes in valve body seperator plate, and adjust your line pressure up. Also have to remove a couple steel balls of om VB. Change you fluid and filter while in there, then readjust your kickdown lever per Haynes manual instructions. You won't believe the difference.
     
  17. AJ/FormS

    AJ/FormS Well-Known Member

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    Heres something to do; open the hood, disconnect that linkrod off both ends and go put it on the workbench.
    Jack the car up slide under there, unhook the the little short KD lever and wire it as far back as it will go. Jack the car down.
    Now take it for a roadtest.
    Any difference in the upshift speeds?
    If yes then you have misadjusted the KD mechanism. The goal is not to just have the linkrod as far back towards the firewall as possible.The real goal is for that above action to then push the KD lever at the tranny towards it's fully rearward position.
    When using a 2bbl throttle bracket on a 4bbl engine this does not occur because the linkrod on top is too short. The cure is to cut the rod apart and lengthen it, until it does.
    Another thing that happens when using the 2bbl bracket on a 4 bbl engine is that the exposed portion of the throttle cable is too short, between the carb loop and the long metal ferrule. Some guys just clamp the cable on the black plastic part. This is a bad idea, cuz it now wants to squeeze the outer sheath against the inner cable and is a recipe for disaster when the throttle sticks wide open. Or sticks in traffic. You will be up some poor souls tailpipe before you can react and shut the key off. I hope you are not one of those guys. There is no cure for this except the proper 4bbl bracket, and the proper 4bbl cable. Well there is but you need to re-engineer the bracket,or order up the Lokar system.
    And finally if you have not properly installed the cable such that the gas pedal fully opens the carb and it's secondaries,all the way; then it is impossible for the tranny to receive the proper signal from the KD mechanism no matter how you adjust it.
    So after doing the tie-back, and it works, then check out your cable system.

    But if the lever tie-back, makes zero difference, then it is very likely that the governor circuit in the tranny is defective. You will need to perform a pressure test, to prove it.
     
    Last edited: Feb 26, 2017
  18. Bruceynz

    Bruceynz Well-Known Member

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    opps
     
    Last edited: Jan 15, 2019
  19. Bruceynz

    Bruceynz Well-Known Member

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    opps
     
    Last edited: Jan 15, 2019
  20. AJ/FormS

    AJ/FormS Well-Known Member

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    OOPs-OOPs