I hope you guys aren't sick of answering this one yet. If I understand correctly, the tc locks up automatically on a 700r4 (in this case '86 truck 700r4), and the only reall tcc concerns when retrofitting it to an older car is unlocking the convertor? I have done some work to my '86 3/4 ton with the 700r4 and was concerned about what unlocks the tcc. Since this came from the factory with this tranny, do I even have anything to worry about? What would I look for on a wiring schematic to know what permorms this function? The reason I ask is because I have done away with the computer distributor and carb and all the smog stuff...I don't want to burn this tranny up.

Also, when I swapped from the stock feedback q-jet to a 600 edelbrock carb, I had to add an aftermarket TV/throttle cable bracket since the aftermarket intake manifold I am using causes problems with the stock bracket. The linkage on the edelbrock carb sticks farther out on the drivers side than the old q-jets did. Even with bending the bracket, the TV cable doesn't have a straight shot from the bracket to the carb. I can get the up/down part lined up, but not the side to side (hope that makes sense). The TV cable sits in the bracket about .5-.75" offset from the TV cable stud on the carb linkage. Is this a problem? I am using an edelbrock bracket and a weiand 8004 manifold, if that helps any.

What you must provide, at a minimum, is a 12Volt source fed through a normally open switch on the brake peddle. The purpose of the brake peddle switch is to unlock the TCC when stopping so you don't stall the engine. I've heard of guys arranging relays on the brake light circuit in place of a switch. Seems like the tech reference section on this site might have some details. The relay idea is a cleaver method.

Lockup is controlled a couple of ways internal to the transmission. The simplest and most common method consists of grounding the TCC solenoid through the 3rd or 4th gear clucth switch which is screwed into the valve body. You've got to drop the pan to hook it up. Also, some earlier 700R4 transmissions had a hydraulic lockup valve.

The pressure switch type will cause lockup to occurr at the same time the transmission shifts into 3rd or 4th gear. The hydraulic type will engage the TCC somewhere between 3rd and 4th gears. If you want to know more about this, search the archives. A guy name larry of lnjstreetrods told us about it. I believe you have to aquire a pre 86 valve body to get hyrdraulic lockup, but I'm not sure of all the technicalities involved.

Often you'll see 700R4 lockup kits for sale. Usually costing about $100. The only thing this provide is a nice connector, the switch, and a vacuum switch. The vacuum switch is designed to drop the TCC when you demand power from the engine. I always figured I could aquire a vacuum switch somewhere for less than $10 and rob a connector from the junk yard for about the same money.

-dnult

go here 700r4 info (http://www.montecarloss.com/SSThunder/drivetrain.html)

I agree with dnult. U used the brake light switch and a relay to get the signal for the ECM. Originally the Corvette setup, where my engine and rtranny are coming from, used a separate switch at the brake pedal.

MK

I tried to find that relay setup in tech reference, but it's not there. Not sure where I saw it. I can summarize by saying you need to connect one side of the relay coil to the brake light circuit. The other side of the coil should be grounded. The transmission power feed for lockup should come from an IGN source through the normally closed contacts of the relay. This way, the relay engergizes when the brake is pressed and opens the circuit to the transmission. Very clean and simple modification compared to adding a separate switch.

-dnult