904 Kickdown issue

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wes beem

wes beem

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The 904 in my duster started leaking pretty bad out of the dreaded shift shaft seal, so i had my spare transmission installed.

The issue is, on my old transmission, the kickdown pivot has spring tension on it that pulls it to the correct position and holds it there, and the new transmission it does not, so there's nothing to push the kickdown lever to where its supposed to be when not under throttle and it just freely moves side to side.

Any idea how to fix this? I didnt catch it until the transmission was already installed and its hard to see whats going on under there.



53610124532_8f89f59d99_c.jpg
 
Sounds like there's something wrong in the valve body if that's not returning.

Smarter folks than I will weigh in

Should be an internal spring that returns it

@lkopaska

Screenshot_20241028-095911_Chrome.png
 
I was thinking the same thing, but ive also seen some with an external spring...and im not sure if diff years were maybe set up diff. I know mine is an earlier one. 68 i think.
 
This is a 78 998 (904 with lockup TC)

All the way forward
1730131664047.png


No spring pressure to here
1730131683147.png


Then spring pressure to the full rear position that returns it to the mid position
1730131702874.png


My recollection is that the earlier (pre 70 something) trans had a "Throttle Position" valve and later ones had a "Kickdown" Valve, might be a difference there?

BUT the return in 67 is a spring on the throttle lever itself to the Kickdown / Throttle position rod at the carb
the spring attaches to the post on the throttle lever. This is the 4BBL version, 2bbl is similar, and pulls the kick down linkage tight to the throttle linkage which will return the kickdown linkage to full forward position due to the throttle return spring.
1730131934631.png


some info but based on 71-72 cars


1968 info

 
Last edited:
Sounds like i just need to hillbilly hotrod up a spring then, because i don't have the factory kickdown linkage or carburetor/intake, ive got a lokar cable and eldelbrock carb with aftermarket styled brackets ext.

Thanks!
 
wes beem said:
Sounds like i just need to hillbilly hotrod up a spring then, because i don't have the factory kickdown linkage or carburetor/intake, ive got a lokar cable and eldelbrock carb with aftermarket styled brackets ext.

Thanks!
Click to expand...

With the locar stuff you can put a light spring from the lever to your cooler line.
I used a small section of 5/16 vacuum line around the cooler line to protect it.

The throttle pressure valve does have a spring inside the valve body under the valve, but that only partially returns the lever.
The added spring on the lever itself solves that.
 
TrailBeast said:
With the locar stuff you can put a light spring from the lever to your cooler line.
I used a small section of 5/16 vacuum line around the cooler line to protect it.

The throttle pressure valve does have a spring inside the valve body under the valve, but that only partially returns the lever.
The added spring on the lever itself solves that.
Click to expand...
i think that's exactly how im gonna address it. Thanks for the idea
 
wes beem said:
i think that's exactly how im gonna address it. Thanks for the idea
Click to expand...
If the lokar does not have a slotted section at the throttle linkage the throttle return spring will do that.

I'm not familiar with the Aftermarket stuff
 
Dana dart showed the correct factory stuff. If using lokar do something like this. (& I wouldn’t hook it to the trans cooler line)

IMG_5249.jpeg
 
TrailBeast said:
Put . small piece of fuel line around the cooler line and it can’t hurt a thing.
My daily driver has been this way for 7-8 years.
Click to expand...
Surely there's a better way to do that. One that won't risk damage to the cooler line or other mounting point Why create potential problems for yourself I guess you do what you gotta do when it comes down to it
 
Fixed mine. I just got a longer spring and attatched it to the front of the transmission housing through an empty hole with a nut/bolt. Shifts and runs just like its supposed to now. Thanks for the ideas guys
 
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