Kickdown wiring for a TH400 ('66 Electra)?

exchaoordo

exchaoordo

Member
Please help me understand and wire up my kickdown solenoidkickdown solenoid.jpg

I think I want to wire a white/black down to the transmission, but I don't understand where that would get power from. I don't understand the wiring diagram that shows the Switch Pitch & Downshift solenoid. Here's some details and a few pics. There is a t-shaped connector at the transmission and pigtails coming from the solenoid: one pair white (or very faded yellow)/black; the other pair is twin grays. At the joint in the throttle rod there is a switch that appears to have been wired to the solenoid.1631896904298.png
tranny switch.jpg
 
The switch you describe as "wired to the solenoid" is the idle switch and should be wired to the kick down switch as shown in your picture. The orange wire supplies power.
The black wire goes to the horizontal terminal, and the white goes to the vertical terminal.
The orange wire should supply power.
 
So now I'm wired up and, after a struggle, got the idle microswitch to close properly. What I don't know is whether all of this is having the intended effect. The car still seems to creep pretty hard and I'm not feeling a kickdown. Is there a way to test the solenoid at the transmission end? I have a bad feeling replacing that involves opening the transmission.
 
exchaoordo said:
So now I'm wired up and, after a struggle, got the idle microswitch to close properly. What I don't know is whether all of this is having the intended effect. The car still seems to creep pretty hard and I'm not feeling a kickdown. Is there a way to test the solenoid at the transmission end? I have a bad feeling replacing that involves opening the transmission.
Click to expand...

It's very simple to test for stall change. The connections at the transmission look like this,

detent.jpg

The horizontal spade is the switch pitch, the vertical is the kick down (from the factory). Attach a jumper wire to the + battery terminal. With the engine off, touch your jumper wire to each spade. You should hear a distinct click. That would be the solenoid inside the pan. There is one for the kickdown attached to the valve body. The switch pitch solenoid is attached to the pump. Each one should click. If you don't hear the click, it doesn't necessarily mean the solenoid is bad. It could be the wiring inside the pan. You'll have to drop the pan to investigate. The kick down solenoid is easy to replace, it attaches to the valve body with 2 bolts. The stator solenoid involves removing the front pump. That requires removal of the transmission. The wiring inside the pan can also be a problem as mentioned. It is also possible that the wires are reversed inside the pan. I have heard of that too.

If you add a toggle switch to your jumper wire, you can attach the wire to the switch pitch spade, start the engine, put the transmission in gear, and flip the toggle switch back and forth. 12 volts gets you high stall, take it away, low stall. You should be able to hear the RPM increase with high stall, and feel the easing of the push. Of course if you can't hear the click of the solenoid, the preceding test is unnecessary.

There is also the possibility that the transmission has been converted in the past and may no longer be a switch pitch. Would not be the first time I have seen that. Lots of things get changed in a 50+ year old car you haven't owned since new.
 
Last edited:
LARRY70GS said:
It's very simple to test for stall change. The connections at the transmission look like this,

View attachment 13216

The horizontal spade is the switch pitch, the vertical is the kick down (from the factory). Attach a jumper wire to the + battery terminal. With the engine off, touch your jumper wire to each spade. You should hear a distinct click. That would be the solenoid inside the pan. There is one for the kickdown attached to the valve body. The switch pitch solenoid is attached to the pump. Each one should click. If you don't hear the click, it doesn't necessarily mean the solenoid is bad. It could be the wiring inside the pan. You'll have to drop the pan to investigate. The kick down solenoid is easy to replace, it attaches to the valve body with 2 bolts. The stator solenoid involves removing the front pump. That requires removal of the transmission. The wiring inside the pan can also be a problem as mentioned. It is also possible that the wires are reversed inside the pan. I have heard of that too.

If you add a toggle switch to your jumper wire, you can attach the wire to the switch pitch spade, start the engine, put the transmission in gear, and flip the toggle switch back and forth. 12 volts gets you high stall, take it away, low stall. You should be able to hear the RPM increase with high stall, and feel the easing of the push. Of course if you can't hear the click of the solenoid, the preceding test is unnecessary.

There is also the possibility that the transmission has been converted in the past and may no longer be a switch pitch. Would not be the first time I have seen that. Lots of things get changed in a 50+ year old car you haven't owned since new.
Click to expand...
Success! We have clicks on both terminals. Very excited and very appreciative. Thanks!
 
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