I have 81 Buick 350C trans in a T-Bucket. This trans has the torque converer lockup feature. It has a switch with 2 brown wires coming out of it on the drivers side. Can this be wired just using a simple off-on switch, or is it a lot more complicaed than that? I would like to use this overdrive feature if possible. Thanks, Tex-T
I'd think you'll need to wire a switch to a relay, then let the power run through the relay to activate the Llock up solenoid. Keep in mind if forget to "untoggle" the switch when slowing down, you can stall the engine.
Ron Francis makes a kit to do that if you want to get fancy with it. Bob http://www.ronfrancis.com/prodinfo.asp?number=TC-75
I don't know about a 350 but with 700's I've hooked up I've used a vacuum switch to monitor engine RPM and a switch on the brake peddle to shut down the converter when you apply the brake. You should be able to google wiring for 700r and find a diagram. I've gotten parts from salvage yards from fs p/u and vans.
Vacuum switch = bad.. from my research I have found that a majority of people that have had them switched them for something else because the tranny was always hunting back and forth. pressure switch is the way to go. everytime the switch reads certain pressure it locks it up and unlocks it when tranny is wanting to downshift.
don't let any one bullshit you...I've hooked them up,ground 12volts to the switch on the dash just that easy! but you have to remember to shut it off when you want to stop, it keeps on pull'n!!
1st- you need to see how many solonoids are in the tranny. All you need is 4th gear lock-up. You can remove & plug the other ones if so equipped. Most of the 4th gear solonoids are self grounding & only have a single wire. Drop the pan to verify what those 2 wires run to. For a T bucket- all you need is a 80 Corvette brake switch. It will have 2 brake terminals (NO) and an additional 2 connectors for cruise control (NC). Use those for the lock-up (disengage lock-up when you hit brakes). On such a light car- a vacuum switch is not needed. So- it's a 12v ignition wire to brake switch (NC terminals) and then to trans plug. Simple as that. You can use a toggle if you want (instead of brake switch) but I didn't. I'm sure I'd forget & leave it locked up & stall the motor. This is simple & works.
Thanks for the help on this guys. I didn't want to screw up my trans, and was not sure of the proper way to go. Tex-T
On my 700R4 I use a GM plunger type brake switch that has a normally open switch for brake lights and a normally closed switch for the lock-up on the converter. I run a simple dash-mounted toggle switch in series with the plunger switch which allows me to disengage the lock-up . Not complicated.
In my expirience the 350C lockup gains about 300RPM when it locks the converter. It is not worth the effort. Just use it like a regular 350 and drive it. You need to change to either a 200R or 700R4 if you want a real overdrive.
And I am finding that the 700 R4 isn't all that simple to hook up either. It's tricky to get the cable pull just exactly right for the shifting timing. On a non-stock hookup you may not get it exactly right. The 350C should net you about 2-3 mpg (300) rpm over the long run on the highway. Simple 12 volts to the plug on the driver's side will activate it. And like the others - turn it off or you'll wonder where the power went when you stop! The real beauty of the 350C is its simplicity. An adjustable modulator will allow you to separate the timing on the shifts to some degree and a change in the springs in the governor will change how sharply it shifts. Very little work and money for a lot of control. And it is one tough tranny. My .02 after researching the poop out of it and talking to a couple of pros that work on these things for racing all the time. For most street cars $30 and some time and you're good to go Be well Steve
Its not really worth it on a 350C. I've hooked up at least 4 700s. All I do is run a switched 12v wire to a toggle switch. From there I go to the transmission connector. Inside the trans the hot wire goes to one wire of the lockup solenoid. The other wire of the lockup solenoid goes to the 4th gear switch. I leave the toggle switch on all the time since there is only power when the ignition is on. With the ground wire of the lockup solenoid going to the 4th gear switch, it will only lock the converter when it shifts to 4th gear. If you have the TV cable adjusted correctly, it will downshift fairly easily and quickly which kicks it out of lockup. I bought a vacuum switch to install with it but never needed to add it.
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