Th350c lock up wiring

[Billys44s]

Hey guys

I recently bought a th350c for my 86 sqaurebody and my truck never originally came with the th350c and once I got the tranny home it came with this connector for what I assume is the lock up, its a 3 pin connector if anyone could tell me how to wire this up I would appreciate it I’ll post a pic of the connector below

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[Matt69olds]

2 wires are power a d ground for the solenoid, the 3rd is for the 3rd gear pressure switch.

The easiest way to wire it is to use the pressure switch to provide a ground to the solenoid once the trans makes the shift into 3rd gear. You just need to make sure the switch is NORMALLY open with no pressure. Some switches work backwards, they are ground until the switch is pressurized, then the ground is removed. The solenoid power feed can be provided thru a toggle switch, brake switch, any number of ways depending on how fancy you want to get.

 

[Goldie Driver]

I'd recommend putting a toggle switch in there even if you dupe the factory wiring.

I did not know how the wiring is done so could not answer prior , but can tell you the factory set up will cause it to kick in on low speed traffic crawls when engine vacuum is high.

The toggle switch allows you to stop that.



The clutch effect is mild on Goldie at freeway speeds, but I am sure every little bit helped meet the specs when new.

Good luck!

 

[pduffyd]

Same wiring as on my old 84 Monte ss I used to have. I pulled out my 350c and stuck a 700r4 and that plugged straight in worked a treat, and got overdrive.

I would definitely use a switch so you have control of the converter lock up.
Also I would get power from the brake light switch ( if you have the one with one side feeds 12v in, one side feeds the brake lights, and the third is for feeding a TCS lockup/cruise control).
Basically, when you step on the brake it unlocks the torque converter, or if you manually turn off the switch.

I will look for the diagram.

found it

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OK, so bypass the ECU, join D and B together (4th gear switch is your 3rd gear or top gear). You can see in the diagram the TCC brake switch to supply 12v to pin A.
As you do not have an ECU to control this trans, add a simple toggle/rocker switch between the TCC brake switch (12V supply via a fuse) and pin A.
One extra thats "A nice to have" if you get a switch with a light on it and wire the light across A and D you can see when your lock up is engaged when top gear engages.

Hope that helps a bit. Oh the letters should be either cast on the bottom of the plug, or you should be able to see the markings in the socket on the trans.