TH400 Kick-Down Not working

[Chuck-68-Cam]

Sorry for another post guys. I am doing a lot of reading but the odd ball stuff is killing. That's why I am here...LOL

Anyway, I just got this vehicle, bought it in TN and drove back to Pittsburgh. Drove great, but kick-down never worked the whole trip.

So I researched and found all the ways to test kick-down. Here is what I did to diagnose.

1.) Ran hot wire to one terminal of switch and grounded the Carb bracket. At about 3/4 throttle, 12 volt passes through switch to wire running to Trans.

2.) Checked wire to trans and connector. All is good.

3.) I turned down the radio and ran the switch again and can clearly here the solenoid in the trans being activated.

So based on my reading, everything is GTG...But it's not. Any ideas? Maybe I missed something?

Thanks

[Chuck-68-Cam]

A Hopeful 1 time bump. 

[elcamino72]

I think what you are saying is that you think you can hear the solenoid in the valve body working when powered through the switch.  If this is true then I would initially suspect that your modulator is either not adjusted properly (if its an adjustable unit) or the wrong modulator.  Here is a link to adjusting the modulator.  https://www.chevelles.com/threads/how-much-to-adjust-vacuum-modulator.146481/

[Chuck-68-Cam]

1St I heard of that. Thanks, something I can at least look into.