abram

Anyone ever installed an aftermarket kickdown switch on a t400 Tranny?
No idea how to do this or which one to buy??
AL

joe_padavano

Um, why? What's wrong with the factory switch?

The kickdown function is a solenoid valve inside the trans. The switch is simply a throttle-actuated switch that closes at wide open throttle and provides +12V to the trans connector. Couldn't be simpler.

citcapp

B& M transmissions makes a kick conversion kick down kit for aroud 56 bucks. Lokar makes one but it is very espensive. You can build one yourself with a normally open monatary contact electrical switch from the electronics store. Fab a bracket that has the carb linkage push on the button when your at full throttle. Oldsguy built one. PM him I think he has a picture of what he did

MJAKS462

My 72 Cutlass has the original 400 trans but has a 78 403 engine. There is no kickdown cable or switch or cable anywhere by the gas pedal or carb. I see the male elec connector on the trans though. also it seems like some linkage is missing , there is a bracket on the trans with nothing attached to it. anybody got a pic of what it should look like finished and some info on what I need to do and buy. Thanks alot.

joe_padavano

Are you sure the TH400 is original to that car? In 1972, the TH400 only came behind the 455. What's the VIN - that will tell you what engine was originally installed. A factory TH400 car will have the switch on the accelerator pedal. I find it hard to believe that someone would have removed it.

compedgemarine

also what bracket is on the trans? if this is column shifted and there is a bracket bolted to the pan behind the shift arm that was for a floor shift cable and not from your car. if yours is floor shifted and you mean the two ears on the shift arm that is for the linkage that goes up to the column for the key lock.

MJAKS462

Here is the vin : 3j67k2m198632

Cowl
ST 34267LAN421747 BDY

TR977 26A PNT

03C A51
I replaced the trans pan and filter yesterday but I did not put the bracket that was further back on the driver side pan back on because my 6 year old was playing with it and he does not know what I am talking about when I ask him where he put it. I dont really remember what it looked like.

compedgemarine

that is the bracket for the floor shifter cable which sounds like you do not have. I would guess that this is not the original trans for the car. as Joe said the only cars that had the TH400 also had the 455 engine. if it originally had a TH400 it would have an electric kickdown switch on the top of the gas pedal inside the car.

70 cutlass s

Your vin indicates the car came with a 350 with a 4barrel carb. 200hp. That would mean it had a th350 from the factory.

MJAKS462

I do have the shifter cable , the car shifts gears right now , but the cable is not hooked to the brackets there.
I will go see where in the heck the cable goes , be right back.

MJAKS462

Sorry I am a no brain.
The shifter cable is hooked to the bracket closet to the front of the car,
so I must be completly missing the kickdown setup , thats what the other bracket that went missing yesterday must have been.
So I guess I will need a switch and cable to hook to the gas pedal and trans.
anywhere I can get a diagram? Thanks and sorry again. John

compedgemarine

some where in here things are getting confused. if you have a floor shift the cable housing will be mounted to the shifter body with a clip in the car and on the trans behind the shift lever will be a bracket held to the trans with two of the pan bolts and the cable housing will be mounted to it with a clip. there should not be any bracket forward of the shift lever. as for the kickdown it will work fine with out it. the only thing is it will not downshift on its own when you go to wide open throttle. there is also no cable for the kickdown, only an electric switch on the throttle pedal and wiring in the harness that goes down to the built in switch on the rear drivers side of the trans. my scanner wont work or I would post the factory drawing of it all. maybe someone here can post one

joe_padavano

Correct. That's why there is no kickdown switch on the accelerator pedal.

citcapp

Its not difficult to manufacture a bracket the bolts to the intake manifold and use and normally open switch the actuates from the carb linkage to operate the kickdown. Oldsguy did it perhaps he can post a picture, or you can buy a kit. or find a pedal assembly in a junk yard. In any case its not that hard of a project.

MrRocket

On my 74 Cutlass the pedal assembly has a place for the kickdown switch. I put a 400TH in my car that had a 350TH factory. Check your pedal to see if it might be a universal part. Then if it is all you have to do is get the switch and hook it up.

MJAKS462

I know its been awhile since I posted this but I am ready to instal the switch.
I have the switch with 2 spades and bracket for the gas pedal and factory two spade female plug is by the steering column under the dash.

Now my question is where does the other end of the wire that I am hooking up to the transmission go ??

joe_padavano

There should be a plastic plug with a spade terminal on the driver's side of the trans.

MJAKS462

Joe I have that connection , but my question is , Where does the other end of that wire go ?
Also I just hooked up the switch that came with the bracket. It does not seem right because the gas pedal I have is for kick down linkage. There is a slider bar on the switch that gets pulled by the gas pedal . It seems like I should have a differant gas pedal assembly , I can not even get the pedal to the floor now because the switch slider runs out of room to slide.

joe_padavano

One of the two wires in the connector on the switch is +12V and the other goes to the wire to the trans. This wire should be taped up in your engine harness somewhere. It's usually a black wire with an orange stripe. You may actually have two wires, one the black/orange one and one green one. The green one would be for the transmission controlled spark system.

The switch is adjustable on the bracket. You should be able to loosen the mounting screws and slide it closer to the firewall to allow the throttle to go all the way to the floor. Note that your TH350 pedal will have the second tab for the kickdown cable. This needs to be cut off for the switch to work properly.

MJAKS462

Makes perfect sense.
I will cut the tab off.
So If I can not find the wire that you refer to up in the dash I will tap into the wire on the harness that is NOT 12v pos and run it to the trans switch.

joe_padavano

That will work, but check the harness that comes out of the connector under the master cylinder. It should be there.

Edit:

The black/orange wire should be in the bottom row of the engine harness connector, which is the outboard half of the firewall connector. The green wire, if there, should be right next to it.

MJAKS462

OK , good to go ! now for the final question , not sure which way the plug goes on the switch .should the pink or orange wire be closest to the firewall ?

joe_padavano

It doesn't matter. All the switch does is connect those two wires together.

MJAKS462

Ok , I am done except I am out of gas , so I will let you know how it works tommorrow. Should be a huge improvement in performance , but I still need a tune up.

MJAKS462

Oh yea , Thanks again Joe , I owe you a beer !

MJAKS462

Took it for a spin today and still no kickdown/downshift.
Have 12 v to the transmission terminal when switch on pedal is activated so I am thinking it may be bad switch at the transmission?? Or is there anything inside the trans that could cause the problem. Thanks

joe_padavano

OK, if you have power to the black/orange wire when you floor the pedal, then the problem is in the trans. Do you have a single terminal connector on the trans or a two terminal connector. The wiring inside the trans is very straightforward. There's a solenoid valve bolted to the valve body - drop the pan and you'll see it. The ground is through the bolt and there's a single wire from the solenoid valve to the connector on the trans case. You should be able to hear this solenoid click when you floor the throttle with the key in RUN. If it doesn't click and the wiring is intact, they you need a new solenoid. If the solenoid clicks but is still doesn't kick down, the problem could still be a sticky solenoid valve (if you're lucky) or more significant problems inside the trans.

MJAKS462

I have a single terminal on the trans , I hear no click from the trans when I floor the pedal , so I will move on to a new solinoid. I just hate to drop the pan again because it is so hard to get it right so it dont leak. But I guess I need to take the pan off again or deal with no kickdown which is not the end of the world , it is just a cruiser anyway.

joe_padavano

Before you buy a new solenoid, you might want to test the old one off the trans, just for grins. The case goes to ground and the wire gets +12v. If it clicks, there's a connection problem somewhere. If it's silent, it's definitely bad.