How is 700r4 lock up controlled in a 1984?

[HotRodPC]

Its currently in CA but headed to AK (where I registered it when I bought it a few months ago) so no smog needed forever and ever!

Take that COMMIFORNIA !!! And right on up that Cali Bear's ass too !!!

 

[5akman]

You bet!

 

[Camatruder]

Does anyone know how the lockup is triggered to disconnect? I use my '91 K5 with stock 700R4 as a daily driver which includes a lot of highway driving. When crusing at 75 mph and have to slow down a little f.e to 70 mph and then when traffic in front of me clears up and i push in the gas pedal to do 75 again a very bad vibration sometimes occurs. If i quickly release the gas pedal and then push it back in all is fine. It feels like the lockup is not disconnecting but i'm not sure it should. All u-joints are good and again this only happens every now and then.

 

[Jrgunn5150]

It's triggered electrically off the brake pedal.

 

[Camatruder]

So if i don't brake, i won't disangage ? And do you think the issue i described is due to this?

 

[Jrgunn5150]

So if i don't brake, i won't disangage ?

Until vacuum forces it.

 

[spanky55amg]

Ok, I'm digging this up as I have an 84 that was originally a TH350 and sometime updated to a 700r4.

It's should have a vacuum switch, low vacuum tcc switch, which when high vacuum is applied, it disengages the tcc. Also there is a brake pedal switch that does the same thing.

I haven't seen the wiring diagram for an 84 yet, but most of the others I have seen, the brake switch and vacuum switch are parallel.

From what I have gather, the low vacuum switch is on the drivers firewall next to the brake booster. But I have heard that the TH350 had the same thing??? I didn't think the TH350 had a lock up converter.

Anyone have ideas or can correct me?

 

[Cuba]

It does have a lockup on 80 and up... what it doesn't have is overdrive. It's not like the TCC on a 700R4 though. It's a pressure type switch near the governor, I wanna say... but don't quote me on that part.

 

[Honky Kong jr]

I wanna say... but don't quote me on that part.

Oh I am you said it...

 

[74 Shortbed]

But I have heard that the TH350 had the same thing??? I didn't think the TH350 had a lock up converter.

Anyone have ideas or can correct me?

They don't, that would the "TH350C" that has a lockup not the TH350.

 

[Cuba]

They don't, that would the "TH350C" that has a lockup not the TH350.

Ah ok... which is the 80 & up, correct?

 

[74 Shortbed]

Ah ok... which is the 80 & up, correct?

I believe they were made between 80 and 86 IIRC??..

 

[spanky55amg]

The low vacuum switch should be by the brake booster and have three wires though, correct?

From other vehicles, because I haven't found a c10 schematic, has brown and blue wires.
And it shouldn't matter which vacuum port it's connected to on the Qjet, correct? As long as its one of the small ports.

 

[HotRodPC]

It does have a lockup on 80 and up... what it doesn't have is overdrive. It's not like the TCC on a 700R4 though. It's a pressure type switch near the governor, I wanna say... but don't quote me on that part.

While this true, it's still activate the same way to the best of my knowledge via Vacuum Switch near the brake booster on the firewall. Now the plug at the trans end may or may not be different.

 

[74 Shortbed]

It does have a lockup on 80 and up... what it doesn't have is overdrive. It's not like the TCC on a 700R4 though. It's a pressure type switch near the governor, I wanna say... but don't quote me on that part.

Nope, works like a 700 it has a solenoid on the case inside the pan electrically controlled, but how they wee activated I have no clue.