55 overdrive

[fast fredy]

Hi guys . Is there anyway to check operation of the kickdown switch , car is not on the road yet but I want to check the switch before installing carpet . I put a test light on the coil wire and pushed the switch thinking that it would momentarily cut the light but it did not . I dont know if the car has to be at certain speed to be able to do this .. If I ground the governor I here the relay click . Maybe if I check the test light with the governor grounded , that test might work . What do you think . I'm try not to have to take out the kickdown switch as it looks like a pain.......Thanks Fred

 

[40cpe]

Check at the switch. Checking across the bottom two connectors should have continuity while the top two are open without pressing the switch. When the switch button is pressed, the top two should have continuity across them with the bottom two open.

 

[dmsfrr]

Do you have a '55 wiring diagram that shows the overdrive hook-up?
A few OD links that might help you out...

https://www.ctci.org/overdrive-kickdown-switch/

https://www.ctci.org/overdrive-and-power-window-relays-bench-check/

https://www.ctci.org/bench-checking-an-overdrive-solenoid/

https://www.ctci.org/servicing-the-overdrive-transmission/

 

[rotorwrench]

The K-D switch performs two functions at the same time. The relay power is killed and the solenoid drops out. The coil kill function is performed through the solenoid just before it drops out so it is included in the mix. There are two sets of points in the solenoid. One controls the two different solenoid coils, ie engage coil and holding coil. The other is for the ignition momentary drop. The coil power is only cut for a split second so it may not work the test light. It would likely only flicker a bit.

I use a digital ohms meter to check the switches. They can be checked with a power circuit and test light but I would isolate the switches before doing that.

 

[fast fredy]

Thanks very much to everyone that replied , these replies give me great info to help me have a better understanding on how to proceed .. thanks again Fred

 

[Alaska Jim]

you might as well leave the carpet loose, as you may have to adjust the height of the switch ( it is adjustable ) to get it not to kick down to early, if set to high, or not at all, if it is set to low.
you can put the carpet in, just don't fasten it down so you can work your hands up under it. I have found that it is a trial and error deal, unless you have the old one to measure how much sticks through the floor before you remove it. I drive mine and get it set correctly before I fasten the carpet and install the sill plate

 

[rotorwrench]

The throttle should be capable of going wide open. This puts the electrical contact for kick down at the WOT point.

 

[miker98038]

There’s one more thing about the KD sw adjustment on a 55. There should be a spring loaded link in the throttle linkage. Wide open throttle hits the stop on the carb. Pushing thru the link activates the KD switch. I’ve had this on 2 55 birds, but no one ever mentions it. It’s listed for the o/d and Fordo, but not for 56. No one ever mentions it, if anyone knows the specifics, it would be interesting to know. It shows out of stock. Thanks to Kultulz for this link.

https://www.npdlink.com/1955-1957-thunderbird/air-fuel/accelerator-pedal-linkage