Switch Pitch TH400 switch

Old Feb 18, 2021 | 07:16 PM
  #1  
425HP409's Avatar
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Switch Pitch TH400 switch

I have checked the solenoids in my transmission and they click with voltage, but I have no electric kickdown and wonder if the switch pitch is working. Is the switch repairable, or does anyone have a known good one?
Old Feb 19, 2021 | 01:39 AM
  #2  
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Recent post here for big cars but switch is same.

https://classicoldsmobile.com/forums...vicing-149216/
Old Feb 19, 2021 | 08:05 AM
  #3  
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Originally Posted by 425HP409
I have checked the solenoids in my transmission and they click with voltage, but I have no electric kickdown and wonder if the switch pitch is working. Is the switch repairable, or does anyone have a known good one?
Do you get power from the pedal switch? Noted in above post. Maybe the contacts inside are burnt or worn.

Last edited by edzolz; Feb 19, 2021 at 08:08 AM.
Old Feb 19, 2021 | 11:15 AM
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Like what Ed said. I think you should, off the top of my head, get no power to the kickdown until floored, and get power at part throttle only to the switch pitch. There's three contacts on the armature, one is ign power in and the other two are the two outputs mentioned.
Old Feb 19, 2021 | 11:29 AM
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Originally Posted by 425HP409
I have checked the solenoids in my transmission and they click with voltage, but I have no electric kickdown and wonder if the switch pitch is working. Is the switch repairable, or does anyone have a known good one?
When you say "they click with voltage", does that mean you can hear them click when someone presses on the accelerator, or did you just jumper 12v to the solenoid terminals on the side of the trans? If they click with the accelerator (with the key in RUN, obviously), then the problem is internal to the trans. Could be the orifice in the solenoid is plugged, or it could be something internal to the trans. FYI, the way both of these solenoids work is that energizing the solenoid opens a vent hole in the hydraulic circuit that vents pressure to move the associated valve and activate the function. If the orifice in the solenoid is plugged, the pressure won't vent and you won't get stator vane movement or kickdown. Of course, if the valves are sticking in the throttle body, the result of no function is the same.

If you simply jumpered 12v to the terminals, then do you know the switch is providing 12v to the trans? Check for voltage at the connector when you step on the gas. If none, trace the circuit to figure out why.
Old Feb 19, 2021 | 05:13 PM
  #6  
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Thanks for the info....
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