Not sure if you could figure a way to make the TH400 passing gear switch work backwards as it is spring loaded normally open, closed at full throttle and self adjusting. Bill
Use the kickdown switch to trigger a normally closed relay. When the throttle is opened the relay opens the 12v circuit and unlocks the TCC.
https://superiortransmission.com/product/superior-k017/ Need to be sure the 700R4 is not the latest 90-93 version, as the kit wont work on those years since the valve body isn't bored for this piston to fit the kit.
Scanned the instruction sheet for mine; just to give you an idea on what's involved with this type. Not saying one system is better than the other, just making suggestions.
How about trying to "dampen" the vacuum signal to the sensor? Years ago many GM vehicles did this in the metal vacuum pipe between the engine and the vacuum modulator to slow its effect. Usually near the engine end of the pipe a small area was neatly crimped down to maybe like .020" or so to restrict the vacuum passing thru it. This dampened how quickly the modulator responded to changes in vacuum and as I recall was to provide smoother shifting at lighter throttle. If you wanted to feel a firmer shift, you could cut the restriction out of the line and replace it with a longer section of vacuum hose. Also, on the rare occasion, the restriction would get plugged and allow little or no vacuum to the modulator, and cutting out the restriction was the quick fix.
See, learnin something new, everyday. Never though of that. Still not sure if its really needed unless the driver is putting it passing gear all the time after TCC is applied.
That's what I did on the ones I have set up. One of these in the vacuum tube going to the vacuum switch. It simply delays the vacuum change.
Information sharing benefits all. Having the clutch unlocked prior to a kickdown not only makes for a smoother driving experience, it also helps to prolong clutch life. The 700r4 clutches are not renowned for their strength if you are running some extra power through them, and we are hot rodding after all......
Wow ! So if I run a hot (switched) 12 volt wire to the red wire on the lockup clutch converter solenoid then the black wire from the same to the 4th gear pressure switch , I assume it would just ground there completing the circuit as the pressure close it , then that's all I need to make it function ? No brake switch or vacuum switch or relay ? That sure would simplify it for sure... So this would be basically the (one wire hookup) that I have heard of.... your explanation makes perfect sense......
And here is how to do it, but you must have a two pole 4th gear pressure switch. This gives you the option of lockup normally as the factory intended (4th gear only), or having no lockup at all, or lock up in second third and fourth.
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