Transmission throttle valve adjustment

[Doorkicker]

727 and using a cable system to the carb for TV to transmission. Everything I'm reading speaks to making adjustments with stock TV rods.

The way I have it currently adjusted is I've set the maximum TV to be at full throttle. But I'm not sure that is the correct ratio. It's not shifting very well.

Basically what is the ratio I should be looking for? For example should the TV cable be engaging the valve early in the throttle position or later in the throttle position?

 

[beanhead]

If you have it set for full pull at full throttle and don't like it, you're just gonna have to play with it a little to find the sweet spot, I know, that's what she said lol....seriously though just back it off a little bit at a time and test. You'll know you went too far the other way if it fails to kick down at pedal-to-the-floor (or you have to go nearly TO the floor if you have a part-throttle valve body). I just don't think there's any set rule as to where to end up with a cable setup.

 

[dvw]

From the results I've seen with throttle pressure cable vs linkage there always seems to be a lot of trouble getting then to function as intended. This is my 2 cents Full back on the lever will give the highest line pressure. If it shifts where you like it at wide open throttle, then that part of the adjustment is correct. If it shifts incorrectly at part throttle with a factory stock valve body and governor? Then the pivot ratio at the carb vs the lever at the transmission is incorrect. The early portion of lever movement doesn't even more the throttle pressure valve in the transmission. You can feel the looseness in the lever when moving it by hand. The pivot point distance between the carburator throttle shaft and cable attaching point may be to close or to far away. The same adjustment can be made at the throttle pressure lever at the transmission itself. Making this change will result in early or later part throttle pressure. Replicating the factory pivot point distances will result in factory shift points. Beyond that either valve body or governor changes need to be made. Aftermarket carburators don't always attach at the factory pivot distance. There is more than one throttle pressure arm style from the factory as well. So after over 60 years the part match may not be correct.
Doug

 

[Wietse]

Currently working on this as well, so I want to share my part as well on this subject.
I am using a (digital) pressure gauge connected on the Line pressure test port on the transmission.
What you supposed to be looking for is that as soon as you move the throttle, the line pressure starts to increase.
At WOT, the Line pressure should be maxed out to whatever the pressure regulator is set at.
This set point can be checked by putting it in Drive, with the brake applied to hold the wheels and slowly increase engine rpm, at a certain rpm the Line pressure will no longer increase and will show it set point. (TV linkage disconnected and force set to max stroke, rearwards)
What i found is that the Line pressure will reach it's maximum pressure without the transmission linkage fully stroked rearwards.
So the carb should be at WOT with the TV linkage on the transmission at that specific point, so you have max. power demand and max Line pressure. (again, this is maybe not at max. linkage stroke)

Depending on any modifications done like reprogramming kits, etc. the line pressure increase is around 30 - 35 psi for a stock style and will give a 40 psi boost in pressure with a Transgo TF-2 kit.
In my example (with TF-2 kit) i get around 90 psi at idle in gear and 130 psi max. TV.

 

[Armyvet25]

Been battling the same thing, still no real success yet

 

[toolmanmike]

Fine tune. I always set mine a little tight, higher, firmer shifts. I almost have it set too high on my Swinger. Low speeds/light throttle, I almost have to back off the gas to make it upshift into second.

 

[Some Car Guy]

I had one of those cable kits decades back. Just never seemed quite right. Back then I was focused on WOT and was scared it would hurt the trans if I set things and it saw lower pressure. Today I would try with the lever all the way forward at idle. That’s my go to for stock linkage rods. See what that does for this deal.

 

[Armyvet25]

eventually I'll have a manual valve body and won't care

 

[Wietse]

With a column shifter it is not as easy...

 

[Dave6T4]

I have used a cable kick down once. I put a LA360 in my '87 Dakota. It had factory A/C, and I could not move the radiator ahead, so I had to move the engine back, leaving no room for kickdown linkage. Getting this setup to work acceptably took a lot of screwing around. The secret to getting it to work, lies in knowing that Chrysler engineered the setup to work with both the carb lever and the kick down lever working in a 1:1 ratio. That is, if the attachment point of the cable on the carb throttle lever moves through a certain range from idle to WOT, the attachment point on the kickdown lever must move through this same range. This may entail drilling new attachment holes in either, or both, if these levers.

 

[oldbee]

It does take a little playing around. I’ve still got my OEM linkage from the original 383. Has a 440 since the 80’s, had to add about 1-1/2” extension to vertical rod coming off bellcrank at rear of engine. Just takes a little playing around on adjustment.