[O52]

No. They were two separate circuits.
The second circuit energized the intake manifold mounted vacuum solenoid in 3rd gear to allow vacuum to the distributor advance. In other words, the distributor only had mechanical advance in first and second gear.
Manual transmissions had a switch built into the case that did the same thing but after third in a 4 speed.

 

[ylwgto]

Thanks guys, for all the info.

Some clarifications:

1. I have to assume the car has the '66 pedal assembly bracketry, but not sure
2. the system once worked! my OLD trans was a '69 TH400 (PX-69-34722). Kickdown used to work on this trans, then stopped. I replaced the switch with the new referenced one while this trans was still in car. No workey.
3. I replaced the old kickdown switch with an identical new switch for TH400s.
4. I replaced the entire TH400 last month with a known fully functioning (including solenoid) TCI Streetfighter trans (later model case with metric bolts). Trans works great, but still no kickdown.
5. single terminal solenoid on old and current trans. Solenoid confirmed hooked up (verified this when I changed the pan)

Writing all this out makes me thing something is amiss in the wiring, so I guess I'll have to go down the test light road.

 

[ylwgto]

So... am I to assume that after all this crap, it's still not downshifting?

yep

 

[armyadarkness]

Thanks guys, for all the info.

Some clarifications:

1. I have to assume the car has the '66 pedal assembly bracketry, but not sure
2. the system once worked! my OLD trans was a '69 TH400 (PX-69-34722). Kickdown used to work on this trans, then stopped. I replaced the switch with the new referenced one while this trans was still in car. No workey.
3. I replaced the old kickdown switch with an identical new switch for TH400s.
4. I replaced the entire TH400 last month with a known fully functioning (including solenoid) TCI Streetfighter trans (later model case with metric bolts). Trans works great, but still no kickdown.
5. single terminal solenoid on old and current trans. Solenoid confirmed hooked up (verified this when I changed the pan)

Writing all this out makes me thing something is amiss in the wiring, so I guess I'll have to go down the test light road.

There would pretty much have to be, at this point.

 

[Ricks68]

I have a 68’ w/2 wire. Changed solenoid in trans. and kick down. Problem I had was it wouldn’t shift out of 2nd gear. Finally disconnected and moved on. Would be nice to have that working though

 

[PontiacJim]

yep

The GTO TH-400 used with the His/Hers option allowed for manual 1-2 & 2-3 shifts (and I know this is not a GTO TH-400). In Drive, the trans acted as any other trans in drive. The transmissions wer coded PB & PT having the manual feature. The trans would not shift out of 1st until you manually shifted to 2nd, there was no RPM, modulator pressure, or governor, override it shifted when you did and you could damage/blow up your engine. The same goes for the 2nd to 3rd shift. Had to be made manually - would not upshift otherwise. Put it in Drive, it went through all the gears and downshifted "as usual." Your trans kits do this. Installed the Trans-Go kit in my brother's tranny and it would manually shift 1-2, 2-3, and automatically when in Drive.

Here is some info from the Pontiac manual on the TH-400. Note it is the 'Detent" that causes the downshifts using the electric switch found at the gas pedal under the dash. I am no expert, but it appears there is the electrically operated detent switch within the trans that does this job. Maybe the detent switch is bad? I would first do as suggested and follow the power from wherever it pulls off of originally (fuse box?), then to the switch. Activate the switch and test for power going out the other connection. If this is good, then keep the switch open, and test for power at the plug on the trans. Looks like you can pull the plug (?), so test both sides of it to make sure there is not a break/malfunction between the two tabs (you know how some parts are reproduced today) If that is good, then it may be an internal problem?