The half moon thing behind the lever with the wires is the neutral safety switch, and or the backup light switch. It has nothing to do with the kickdown.


The thing with the wire on the carb is a fast idle solenoid. It kicks out usually when the A/C is turned on to raise the idle speed so the A/C cools better. They also sometimes use it with a computer for emissions reasons. If you do not have trouble with the engine stalling when driving slow and goosing the throttle, I would not worry about a dashpot.


The long piece with all the vacuum lines in the above picture is the main vacuum "tree" for manifold vacuum. All of those spots are places to tap into full manifold vacuum if you happen to need them.

 

The above problem description is what started this whole thread. If you drive normally, and it shifts fine, then I believe the modulator valve is fine. If the modulator valve was faulty, then the tranny would not shift properly at any time.

If you want to mash the pedal to the floor and expect it to shift, then yes you will need to hook the kickdown rod up. That's what it's job is, not the modulator valve. The only way you will get the modulator valve to kick the tranny into a lower gear is to have a very low road speed, and then mash it to the floor, since it works in conjunction with the governor inside the tranny.

Now that you have the rod hooked up, will it downshift for you? You should be able to push the throttle open, and about 1/2 to 3/4 through the lever travel, it should hit the kickdown rod lever and continue to push on the kickdown rod as you fully open the carb throttle.

 

Okay so am i able to test this parked???

Like pop the hood, start the truck, and hit the throttle. Than around 1/2-3/4 way through i should see the rod move?

 

Do it with the engine off. Only do it once or twice though. Each time you push the throttle back, you are squirting fuel into the engine, and if you do it too many times you are going to flood the engine. If the lever moves, then take it out on the road and see if it works.

 

Also for your road test, make sure you are going slow and are in 3rd gear. If you are going 80mph and expect it to downshift, it won't do it.

 

Make sure that im in 3rd gear?? Well from what i've read this transmission has only 3 gears? So if it was already in 3rd why would it need to downshift and shift back into third?

Also should this work for any gear? Because i could mash it at anytime and it would do the same thing.

 

Okay, well since i was so curouis i went ahead and tested it right now outside in the cold rain lol.

The good news: The rod works, as soon as i get around 1/2 down on the accelerator the rod moves. But, how infact do i know that this is making the tranny shift down? For alls i know that rod is just moving down and not actually engaging anything?

The bad news: It didn't fix the problem...

So while i took a test drive, i tried listening to it and seeing if there was anything else i could tell ya'll too see if it would help.

An now, im not even sure that it will shift into 3rd gear? I can feel a slight tick for the first gear, but then my exhaust somewhat gets into the way and i cant really hear or tell if it has shifted again.

I tried to mash it at a stand still and also while moving (45 mph) and it would do it on both. What happens is the truck will slightly go faster but no where like it should. It will sound as if its revving up in a way and it will feel like its grinding and twisting and wanting to shift or something but it wont actually shift i dont think. But if i let off of it i can continue fowards and it will run fine and pretty smooth.

Would this seem to be a sign that my transmission is going out or is there other compodents that could make it do this? I sure would like to fix this as its starting to worrie me.

Thanks alot ya'll.

 

Any further help please?

I tried moving my my modulator vaccum line to the main vaccum line instead of off the tri-vaccum area mounted on firewall. After doing this i went and took it for a test drive and this didn't seem to help the problem...

It does seem to only be messing up with the 3rd gear. An does the modullator control only the 3rd gear? So would yall recremend i replace this?

 

Here's how it works. You take off normally, the tranny goes 1-2-3, and you are cruising down the road. You are doing around 45-55 mph, and you punch it, and it will downshift to 2, and the engine will rev very high. When you let up it will shift back to 3.

I wanted you to make sure you are in 3rd gear, because it won't work in the other gears. If you are in 2, mashing it will not make it go to 1st.

The kick down rods I had, have a adjustment on the carb linkage. If you look at it and move the throttle, you can see the adjustable lever that hits the rod. Make sure the rod is actuated fully when the throttle is wide open.

If none of this works, there must be something wrong with the tranny.

 

Okay, after school today im going to see if i can adjust the kickdown on the carb linkage.

Now from what i've read, the modulator is what controls 3rd gear correct?

So should i try replacing mine since i've heard they are fairly cheap?

Also does anyone know how to remove it?

Thanks alot guys! If i was able to give out more rep id be glad too.

 

It has been many years since I replaced a modulator valve on a C6, but I believe you simply remove the vacuum hose from the valve and unscrew it from the transmission body, using a socket. Look for a colored ring (green?) on the valve, as the different colors were for various applications... replace with the same color, assuming that yours is the correct one.

In my experience with "bad" modulator valves, as you drive, the vehicle wants to stay in the 1st gear unless you really let off the throttle and then it will shift to 2nd gear. The hose usually had transmission fluid in it (as previously mentioned) and would be swollen and loose at the connection to the vacuum port.

If raising the vehicle, BE SURE TO USE JACK STANDS!!! And make sure no one will bump into the vehicle while you are under it. BE SAFE!!!

 

No worries on the jack stands, its tall enough that i can squeeze underneath and work on it.

Thanks for the tips, i plan on checking the price today at advance before i buy it. But im unsure what else there is that could be messing up the tranny except for the tranny itself so i figure i mise well replace it...

Btw, i check the transmission fluid yesterday when i had it parked and it seemed to be a bit high, could this be a cause for it too act weird? Should i remove the extra fluid? How should i do this?

Also while playing with it all i found a threaded plug on the transmission its self. Is this to remove the fluid or what?

Thanks

 

I think I paid under $10 for a new modulator valve when I changed it out on my truck. You'll want to have a rag or something handy to stick in the modulator valve hole, so all your transmission fluid doesn't drain out.

To remove the modulator valve, unbolt the small bracket that holds the valve in place, and once that's out of the way, pull the valve out of the transmission. There may be a small rod in the end of the valve (resembling a drill bit); if there is, make sure you keep track of it and put it into the end of the new valve. As 1986F150Six said, take note of the color of the band on the valve, so you can get the correct replacement.

The new valve might come with a small gasket; I can't remember if I installed it on my truck since my previous one didn't have one.

Before installing the new valve, get a little transmission fluid on your finger and lubricate the end of the valve (and the O-ring there) that fits into the transmission before you put it in. From here, reassembly is the reverse of removal.

FWIW my kickdown rod on my truck's C6 can be slid completely out of the transmission, since something is either missing or jacked up. Yet if I mash the pedal enough it shifts into what I assume is 2nd.

 

Too much fluid is not good. It can make the fluid foam because it gets up in the moving parts, and foamy fluid is not good for the tranny hydraulics.

Don't move any plug looking things on the side of the tranny. These are usually adjustments and should be left alone. To get the fluid out, you have to loosen the tranny pan, there is no drain plug.

 

Okie doke, from some further reading i believe it said that the nut thing i was talking of is for band adjustment or something of that sort?



NOW! I dont want to jynx it or anything but.... Today i did some work on the truck, including replacing the modulator valve. Btw thanks for reminding me that when i take off the old modulator that tranny fluids going to come out.

Haha, i had to find out the hard way! Let's just say i took a nice shower in the bright red stuff.

Also changing the modulator gave me a good idea for anyone who wants to drain their tranny fluid. Too take off the modulator it only takes one quick bolt. But if you take that off the fluid will come out. If you did this you could make it quite a bit easier on yourself to get rid of most of the fluid at start.

Now, i replaced the old modulator and continued to drain 1/2 quart or so of tranny fluid out. (didn't realize i had that much extra fluid in there) But this is where i was getting at, not that i wanna jynx it or anything but it seems after doing this it has fixed my tranny problem.

Why im not quite sure yet is because i took two test drives. An the more i drove it the better it seemed to get. How much better is what im not quite sure yet. Alittle time will tell on this.

But it seems like it was shifting fine when i punched it going 40-50 mph. But when i tried to punch it going 20-30 it was doing the same ol thing. Which is better than it used to be. But in a few more days ill give yall an update!

THANKS SO MUCH YALL!