what does this plug go to on my Turbo 350?

[x75]

1985 Conquista 305. My transmission has been shifting sortof lazy of late, taking a couple seconds to go 1-2, sometime slow 2-3. Other times it will not shift into 3rd until about 55, wants to stay in second. I found that if I stabbed the gas pedal hard enough to trigger a downshift, then the 2-3 shift goes forward as usual. Other times it shifts just fine, but I think it has something to do with the kick-down setup.

I got under the car and immediately saw this connector was unplugged on the left side of the trans, and looks like been loose for a while.

What does it do?

thanks, I don;t have a reference and all my other cars are standards, so I;m ignorant

 

[shoedoos]

you have a TH350 lockup version of the trans.....with a bit of luck by plugging it back in you could be back on your way, google will tell you the pros and cons of the TH350C trans.....

 

[1320John$$$]

you have a TH350 lockup version of the trans.....with a bit of luck by plugging it back in you could be back on your way, google will tell you the pros and cons of the TH350C trans.....

If you plug it in and the thing bucks and stalls the lock up solenoid is bad and that’s probably why it was unplugged in the first place that has nothing to do with the way your transmission shifts so you got problems elsewhere

 

[timo22]

If it is shifting late, take a look at the vacuum modulator. Make sure the line is connected. If it is , unplug the line from the modulator . Any sign of fluid means a ruptured diaphragm . 1320john is correct.
timo22

 

[gdouaire]

If it is shifting late, take a look at the vacuum modulator. Make sure the line is connected. If it is , unplug the line from the modulator . Any sign of fluid means a ruptured diaphragm . 1320john is correct.
timo22

I second that!

 

[x75]

wow you guys are so helpful!

Tomorrow I will try each recommendation and report back.

Yes the converter seems "loose" at times, seeming to free-wheel between gear shifts. Then later it seems to be locked and I'm turning 1500 rpm going 55-60 mph.

I want this old beast to last. only showing 95K miles and feels like it could last much longer

 

[Bonnewagon]

f you plug it in and the thing bucks and stalls the lock up solenoid is bad and that’s probably why it was unplugged in the first place

I agree. That happened to my Mom's car. Good thing is it is an easy fix. You just drop the pan, trace the wires, and find the solenoid inside. I removed my CCC system and activated the lock-up manually with a toggle switch on the dash. It was worth about 300 rpm on the highway.

 

[565bbchevy]

I have a 350C in my shed that came out of another project car, the plug is just to lock up the torque convertor and the one I have was wired to a switch with a big red light in the dash that they used to manually turn it on, as stated it has nothing to do with the actual shifting of the trans.

 

[Max Headroom]

Way back in the day, they used to make an adjustable vacuum modulator that would move the shift points by turning an adjustment screw inside the modulator. I bought an old POS 65 GTO that had one an my trans shifted just like yours is. One of the local hot rod guys told me that might be the issue and it was. If memory serves, you would unplug the vacuum line and turn a screw inside.

That being said, could you have a vacuum leak or a bad modulator.
https://www.classictransmissionsolu...MIhJW6y8KS7AIVBYbICh0XtAitEAQYAiABEgKje_D_BwE

 

[x75]

thanks for the advice. I reconnected the plug and everything seems OK, quicker shifts for sure. While underneath the car I noticed some thick branches from a tree that were stuck in the frame. At some point the car drove over a branch and it probably knocked the switch plug off the transmission.

My car does not have a vacuum modulator, rather a cable runs from the carb throttle to a switch box between the engine and firewall. I will try to lubricate it