Kick Down...?

[vossy]

Uber-newbie question here.. I crawled under my '71 to inspect a tranny fluid leak, and saw that (what I now know is) the kickdown lever, on the transmission with nothing connected to it..

3 questions:

1- What exactly is the kickdown connection for? Is it more than just controlling the downshifting? (The 'new to me truck' does seem to shift very hard at like 15-20 mph from first, and I assumed that a previous owner had installed a shift kit. Is it possible that the absent kickdown linkage is responsible, instead?)
2- Is figuring out the linkage to the edlebrock carb worth the effort?
3- Can I just leave it flopping around in the wind like it is, or should I 'tie it off' as I've read on other forums?

And, if answer to #3 is to tie off the kick down arm... what position should it be tied to, and how should it be tied off?

Thanks!

[1972hiboy]

I would go ahead and connect it up. it helps keeps the engine in a good rpm range per throttle application.

[cep62]

While it's better to have it hooked up
you can leave it "flop in the wind" with no ill effects.
Unless you're talking about the whole rod that goes up to the carb.
If thats the case I'd either hook it up , or disconnect it at the tranny.

[shortbedCUSTOM]

I'm pretty sure he means that the linkage, which in this case is a rod, is missing all together. I'm in the same boat. Mine is missing the rod all together. Drives fine but the 1-2 shift happens almost instantly after take off and the 2-3 shift is almost right behind it. So needless to say, I'm in third and I haven't even hit 30mph. Pretty good on mpg but has no passing gear.

[vossy]

Exactly, Shorttbed..


Can anyone answer for sure if the kickdown linkage affects the up shift and not just the downshift?

Thanks?

[1972hiboy]

It does effect the upshift. it will hold it in the lower gear longer if the trans senses more throttle application.

[BobbyFord]

I'm pretty sure he means that the linkage, which in this case is a rod, is missing all together. I'm in the same boat. Mine is missing the rod all together. Drives fine but the 1-2 shift happens almost instantly after take off and the 2-3 shift is almost right behind it. So needless to say, I'm in third and I haven't even hit 30mph. Pretty good on mpg but has no passing gear.

Pull the vacuum line off of the modulator valve and stick a tiny screwdriver into the vacuum nipple on the modulator. There is a small screw inside. Screw the screw clockwise 1-1/2 turns. Put the vac line back on a drive it.

Exactly, Shorttbed..


Can anyone answer for sure if the kickdown linkage affects the up shift and not just the downshift?

Thanks?

The kick down rod affects the upshift only at wide open throttle, holding the gear longer.

[shortbedCUSTOM]

[/quote]
Pull the vacuum line off of the modulator valve and stick a tiny screwdriver into the vacuum nipple on the modulator. There is a small screw inside. Screw the screw clockwise 1-1/2 turns. Put the vac line back on a drive it.[/quote]


Can you explain what exactly is happening by doing this?

[BobbyFord]

Can you explain what exactly is happening by doing this?

I'm afraid that would cost you $10.

[shortbedCUSTOM]

C'mon man!

[1972hiboy]

if the modulator is out of adjustment it can change the shift points and or make a firm shift. The kickdown rod also contributes to changing the shift points via throttle application

[cep62]

The kick down rod affects the upshift only at wide open throttle, holding the gear longer

And it will make it downshift when you push on the gas pedal.

[BobbyFord]

The kick down rod affects the upshift only at wide open throttle, holding the gear longer

And it will make it downshift when you push on the gas pedal.

Correct. I was replying to a specific question.

[BobbyFord]

if the modulator is out of adjustment it can change the shift points and or make a firm shift. The kickdown rod also contributes to changing the shift points via throttle application

Kickdown rod only affects shifting at WOT, if it is adjusted correctly.

[BobbyFord]

Under normal driving conditions (non-WOT) the modulator valve (in conjunction with the governor) controls shift points. WOT = no vacuum on the modulator, increasing throttle valve pressure and lengthening shift points. Under light throttle the engine produces vacuum, which pulls on the modulator valve, reducing throttle valve pressure, resulting in lighter, earlier shifts.
Adjusting the modulator valve by turning the screw in, increases line pressure and lengthens the shift pattern (shift later.) Turning the screw counter-clockwise reduces line pressure and makes the trans shift sooner. The kickdown rod increases line pressure manually at WOT.