what does the orange wire from the trans connect to?

Brianmontesa

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Had to pull the trans and motor now all back together and can't figure out where the orange trans wire goes...

Figured it went to the pedal, don't see anything.

Thanks!
 

Brianmontesa

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The vacuum is all hooked up. Haven't started it yet. The sensor is just above the pan on driver's side I think. The trans shop that rebuilt it told me it was a kick down sensor. Like I said, don't see what it would hook to. Looks like I better look at the Chevy book tomorrow.

Thanks.
 

Crash_AF

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It's for the kickdown solenoid. The switch is attached to the accelerator pedal. The vacuum actuates the kick down, but it's a constant source since the diesel doesn't make manifold vacuum, hence the solenoid.


Later
 

patracy

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So much wrong information here.

The wire is as mentioned later correctly, the kickdown switch. However the vacuum line is not for kickdown. The vacuum gives the transmission throttle position. Wanna see? Disconnect the vacuum line and drive it a bit. You'll see the transmission shift late and hard because it sees no vacuum. (And to the modulator, the lack of vacuum would make the transmission think that the engine is at WOT)
 

cucvrus

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Sorry to sound like a know it all. But the TH400 on the CUCV does have an electric down shift. The switch is located on the left side of the trasmission directly below the drives foot. It is the only electric wire that plugs into the transmision. The VCM on the injection pump does NOT control the down shifts of the TH400 in the CUCV. That only controls the up shifts and the timing of the shifts by regulating and sensing and controling the vacuum during acceleration. The orange wire is on a slide switch at the top of throttle pedal and senses when you push the pedal down and then electrically down shifts the transmission to the appropriate gear. Be it first or second. That depends on your speed when you floor it. I hope that helps. And if I am incorrect about minor details in my explanation. I am open for correction. Thank you.
 

Skinny

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Sorry to sound like a know it all. But the TH400 on the CUCV does have an electric down shift. The switch is located on the left side of the trasmission directly below the drives foot. It is the only electric wire that plugs into the transmision. The VCM on the injection pump does NOT control the down shifts of the TH400 in the CUCV. That only controls the up shifts and the timing of the shifts by regulating and sensing and controling the vacuum during acceleration. The orange wire is on a slide switch at the top of throttle pedal and senses when you push the pedal down and then electrically down shifts the transmission to the appropriate gear. Be it first or second. That depends on your speed when you floor it. I hope that helps. And if I am incorrect about minor details in my explanation. I am open for correction. Thank you.
The kickdown does that, force a downshift at around 3/4 throttle. The vacuum is a signal that goes down to the trans via a hose. It attaches to the modulator which creates modulator pressure in the trans. The governor spins off the trans output shaft and creates governor pressure when vehicle speed increases. When you are driving down the road, the 1-2 shift valve has modulator pressure on one side and governor pressure on the other. It simply battles back and forth till vehicle speed goes up high enough or throttle angle (vacuum signal) goes low enough (high vacuum applied) which pushes the 1-2 shift valve. This then applies the correct brake and creates second gear. Now once the 1-2 shift valve moves, it typically will not downshift until one of the pressures drastically changes. The kickdown signal kind of over rules this if you push the accelerator down far enough.

Simple? You passed day 1 in auto trans class.
 
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