Th 400 transmission kick down

[Red71gmc]

I am not a transmission guy as you will be able to tell. From my reading of old post I think I can handle my two issues with a little more info.

I have a 71 GMC with a TH400 transmission. I have a couple things I would like to correct. The first being it doesn't shift down from 3rd when hard pedal is applied. I don't have a kick down switch on my gas pedal but it does have the mounting plate for one. I can get a switch and wiring but where does it hook up at the transmission?

The other is the quick shift from 2nd to 3rd at lower than desired speeds. I have read several old post about that and believe I need to try to adjust the vacuum modulator screw first (if supplied) and then maybe a shift kit.

Should I fix the kick down first? Or does it matter? Thank you