Kickdown fine tune adjustment

-
340,
Is there any particular reason you want to extend the shift speed in each gear?
I always went the opposite way for normal driving. Quick upshifts & let the t/converter do the work.
 
Bewy said:
If you want to increase the 1-2 upshift speed, you can do it without removing the pan.
If you have a carb with large throttle bores, it requires less throttle opening than a carb with small t/bores....to get to the same road speed [ shift speed ]. The K/D lever moves less with a big carb, all else being equal; & the trans shifts earlier, all else being equal.
The above demonstrates that it is a 'ratio thing '.

If you want later shifting: there is a rod from the carb that goes to a bracket/linkage at the back of the engine. Where this rod hooks onto the bracket, the hole or stud on that bracket needs to be repositioned closer to the pivot.
The idea is: for the same throttle open position, the K/D lever moves further, increasing line pressure & delaying the shift point. You might need to experiment with different hole positions. The same thing can be achieved with the K/D lever on the trans; move the linkake hole closer to the
Click to expand...

Bewy said:
340,
Is there any particular reason you want to extend the shift speed in each gear?
I always went the opposite way for normal driving. Quick upshifts & let the t/converter do the work.
Click to expand...
Initially it felt like it was starting in 3rd gear, sluggish acceleration no torque it wasn’t winding out at all. I wasn’t getting any 3-2 kick down either. None when I punched it. Just felt like I was always driving around in 3rd. No upshifts felt.

I then tightened the rod about 3/8” and now I am getting it to kick down under WOT properly. I have a lot more torque. I am however still having trouble detecting feeling/hearing the 1-2 up shift. I feel it might be happening right away.

I still and need to drive it more with a tachometer to see what RPM the shift points are at.
 
Bewy said:
If you want to increase the 1-2 upshift speed, you can do it without removing the pan.
If you have a carb with large throttle bores, it requires less throttle opening than a carb with small t/bores....to get to the same road speed [ shift speed ]. The K/D lever moves less with a big carb, all else being equal; & the trans shifts earlier, all else being equal.
The above demonstrates that it is a 'ratio thing '.

If you want later shifting: there is a rod from the carb that goes to a bracket/linkage at the back of the engine. Where this rod hooks onto the bracket, the hole or stud on that bracket needs to be repositioned closer to the pivot.
The idea is: for the same throttle open position, the K/D lever moves further, increasing line pressure & delaying the shift point. You might need to experiment with different hole positions. The same thing can be achieved with the K/D lever on the trans; move the linkake hole closer to the
Click to expand...

JDMopar said:
When you have it adjusted properly, under normal driving conditions, it should shift from 1-2 at 18 mph and from 2-3 at 28 mph. If it is short shifting (too early) make the rod longer by unscrewing the adjustment at the carb. If it is holding too long and shifting late, shorten that same adjustment a few turns at a time to get it dialed in. Obviously, the more you mash the gas pedal, the more throttle pressure the valve body sees and will hold shifts longer, as it is designed to do. You do not want to lengthen the throttle pressure linkage to the point that it keeps the carb butterflies from achieving wide open throttle, like @RustyRatRod advised above. It is also important to have a small spring pulling the throttle pressure linkage forward towards the carb stud that pushes it backwards. If there is a gap between the stud on the carb and the linkage slot, the valve body isn't seeing any pressure applied from idle to wherever the stud finally catches the slot and starts pushing. Go back up to post #2 and look at the pic. See that little triangle shaped tab welded to the kickdown rod? The little spring goes in the hole in that tab and hooks to the end of the carb stud to hold the adjuster to the rod at all times. Keep plugging at it, and you'll get it figured out.

:thumbsup:
Click to expand...
Thank you yes I need to check that the carb secondaries are being blocked with the latest KD adjustment as Rusty suggested. Wasn’t able to do that today as I had to paint some parts.
 
Bewy said:
340,
Is there any particular reason you want to extend the shift speed in each gear?
I always went the opposite way for normal driving. Quick upshifts & let the t/converter do the work.
Click to expand...
Read the thread, Sparky. He's said all along it shifts way too quickly and doesn't down shift properly. Both indicative of low throttle pressure. If he doesn't fix it and SOON, he'll be puling the transmission for a rebuild. I hope it's not too late now.
 
RRR,
I did read the thread. I like my auto trans to upshift early, & I doubt I am the only one. And they didn't burn up or blow up. I simply asked the question. Get over it.
 
Bewy said:
If you want to increase the 1-2 upshift speed, you can do it without removing the pan.
If you have a carb with large throttle bores, it requires less throttle opening than a carb with small t/bores....to get to the same road speed [ shift speed ]. The K/D lever moves less with a big carb, all else being equal; & the trans shifts earlier, all else being equal.
The above demonstrates that it is a 'ratio thing '.

If you want later shifting: there is a rod from the carb that goes to a bracket/linkage at the back of the engine. Where this rod hooks onto the bracket, the hole or stud on that bracket needs to be repositioned closer to the pivot.
The idea is: for the same throttle open position, the K/D lever moves further, increasing line pressure & delaying the shift point. You might need to experiment with different hole positions. The same thing can be achieved with the K/D lever on the trans; move the linkake hole closer to the pivot.
Click to expand...
I don’t think you can’t really do this as it will inhibit full throttle travel as the the kick down lever will be full open (pushed all the way to the back of the car) before the throttle is fully open. Once the tv lever is fully open it will prevent the throttle from moving further back

With the Lokar set up I used and Dakota lever the ratio is perfect at 1:1. They work in unison and arrive at full open at the same time
 
Last edited:
That is why I said in post #23 it is a ratio 'thing'. You have to experiment. That is what hotrodders do when they are unhappy with the status quo......
 
340 Just wondering if this transmission is being installed with the 340 you were working on to get dialed in? If so a stock transmission, converter and rear end gears come into play here I would think.

I'm not questioning any of the other replies here, good info was relayed.
 
Last edited:
Darter6 said:
Common practice for those that don't know proper adjustment techniques.
Click to expand...
I had a 727 rebuilt, by a Chevy guy and he did this. I never got a good answer why, but it's been working great for a couple years now so I'm leaving it.
 
Mojoe9955 said:
I had a 727 rebuilt, by a Chevy guy and he did this. I never got a good answer why, but it's been working great for a couple years now so I'm leaving it.
Click to expand...
It has the wrong length rod in it somewhere, so the nut and bolt make up the difference.
 
Mojoe9955 said:
I had a 727 rebuilt, by a Chevy guy and he did this. I never got a good answer why, but it's been working great for a couple years now so I'm leaving it.
Click to expand...
I guess it's the old saying "If it ain't broke,don't fix it.!"
 
just so you guys don’t think I’m lazy…… size does matter she was right. But she didn’t know geometry also matters.

IMG_4616.jpeg


IMG_4617.jpeg
 
You must log in or register to reply here.
-

Back
Top