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700R4 vacuum switch ??

I'm not sure if the one I have is bad, but I can't find it at any of the online parts stores. Napa, Oriely's, advanced, zone.. none of them.
 
I'm not sure if the one I have is bad, but I can't find it at any of the online parts stores. Napa, Oriely's, advanced, zone.. none of them.

It's just a simple vacuum switch. normally open adding vacuum will close it.
 
I tried looking one up for my van,at Rock Auto,J.C. Whitney,no listings..

But a google image search shows this one from O-riley's that will likely work--they dont give them away though!..:eek1:...I guess the price is why so many just use a toggle switch on the dash?..It's BWC part # TCL-10 and lists for 63.99..

I'd be looking at boneyards,myself..

tcl10_primary.jpg
 
ya i found the kit on ebay for $119,but that included the wiring harness in the tranny
 
The vacuum switch make the converter go out of lockup when you accelerate . Forces the trans to down shift from over drive to third gear.

No. This is a 700, so it has no kick-down switch. That vacuum switch only relates to TCC lockup. ALL upshifts and downshifts in the 700 are controlled by TV pressure and governor pressure. The circuit is from the brake pedal switch, through the vacuum switch and to the transmission. It unlocks the converter at heavy throttle (or when the brake pedal is pressed, of course).

The other half of the lockup equation is a hydraulic circuit inside the tranny that prevents lockup in lower gears and also high TV. You need the right hydraulic and vacuum conditions to lock the TCC.

The other circuit to the red connector and vacuum switch mounted at the rear of the PS valve cover is for evap system purge. The idea is that your torque converter only locks when you are at cruise conditions. So when it's locked, it's OK to cycle the canister fumes into the engine. It feeds from a switch on this internal hydraulic circuit.

Don't confuse this with aftermarket setups (like the Bowtie overdrive one). They are completely different. IMO, the factory setup is the best one.
 
It does go through the firewall near the peddles so I'm going say you are correct.


Anyone know what the switch is called?

I had a pretty bad set of vacuum leaks and the trans wasn't shifting right so I'm in the process off replacing ALL of the vacuum lines under the hood. It's a mess!

It says right on your underhood decal, it is a transmission convertor vacuum switch.
 
It says right on your underhood decal, it is a transmission convertor vacuum switch.

I'll take a look at the rest of the decal, but it clearly doesn't say that. It might be an abbreviation for that but doesn't spell it out like that.
 
have been looking for that tcc valve since I got rid of my ecm have just been using the old high beam switch on the floor to lock it up manually when i wasn't in OD so just ordered it one of those switches up
 
I'll take a look at the rest of the decal, but it clearly doesn't say that. It might be an abbreviation for that but doesn't spell it out like that.

Yes, it doesn't spell it out in full it is abbreviated but that is what it's called.
 
this one is adjustable

ww.ebay.com/itm/TRANSMISSION-VACUUM-SWITCH-350C-700-700R4-ADJUSTABLE-6-to-22-CUSTOM-Tuneable-/251096417522?pt=Motors_Car_Truck_Parts_Accessories&hash=item3a768344f2&vxp=mtr
 
Bumping this thread back up. I have an '86 K5 with a 305/Q-jet and 700R4. I'm not getting any TCC lockup. I have a good manifold vacuum line to the vacuum switch on the firewall, but I'm not getting any power to the brake pedal switch. The switch does work (pressing the brake pedal interrupts the circuit), but there is no power to the switch on the grey wire. I can't find any blown fuses, but I'm not even sure which circuit it is on.

Does anyone have the wiring diagram for this? Some of my fuse labels are really hard to read; I don't see any labeled TCC, but some are illegible. Does power for this circuit come straight from the fuse box? Does anyone know which fuse I should be focusing on?
 
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