Installing a th400 from mid 60’s BOP w/ switch pitch in 86 C10 HELP

[Preston]

I think I have purchased a different type th400 it has a 2 wire terminal on the drivers side of the transmission (switch pitch) wich I believe (not 100%) that controls the torque converter (stall speed). With a little help from the group I need to figure out the location and type of switch I need. To bring you up to date I had to get an adapter to bolt this up to my fresh 350 and used the torque converter that came with the freshly rebuilt trans with shift improvement kit. I picked up my new custom driveshaft yesterday and installed it, after that I was buttoning up all the shift linkage etc I saw what I thought was an backup light switch (wrong) I’m ready to take her for a spin then I’m second guessing myself just need a little guidance.

 

[Preston]

I have been searching the www trying to find newer post on this mainly to get the latest information, looks like the switch changes the stall speed or torque to eliminate a soft shift and reverse that at higher rpms to get the maximum performance from your engine. I’m just trying to set this up as close to the original set up as possible.
Thanks for your help and or comments.

 

[Wumbo]

Kickdown switch. You'll need a microswitch mounted on the carb or gas pedal to tell the trans your WOT.

 

[Preston]

Do I switch the two pols to 12 volt separately? Or use a double switch to put 12 volts to each terminal separately?

Thanks for the information Think I figured it out Old Man from old school learning every day.Thanks

 

[Wumbo]

Switched power(key ON) -> Microswitch-> Kickdown solenoid -> ground

More proper way to do it incorporates a relay

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[Preston]

Thanks again just need to figure where I want to put the switch and what kind of bracket to use, off to the www to figure that out.

 

[Wumbo]

There are microswitches and brackets designed for nitrous oxide systems that would work perfectly.

 

[Preston]

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That’s what I’m looking at carb mounted with a relay as your schematic shows thanks for your help, can’t wait to get this monster back on the road

 

[Wumbo]

Glad to help

 

[Preston]

One more question I have 2 wires on the transmission the plug has one spade north and south and the other east and west think this more than a kick down switch

 

[Wumbo]

hold up. might be mistaken.

 

[Wumbo]

You want the terminal with the orange wire in this pic.

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Check out this write up, goes over the system pretty well.

https://bangshift.com/general-news/...-kickdown-switch-in-a-turbo-400-transmission/

 

[Wumbo]

Is that a lockup torque convertor?

Nevermind, I completely overlooked the switch pitch convertor.

Thats a little more complicated. BRB.

 

[Preston]

Thanks again

 

[Wumbo]

Your going to need a second switch that switches "off" when carb is at idle.

Same basic wiring, but you want to supply 12v to the switch pitch terminal when you are off idle.