The Stovebolt Site Forums The Shop Area The HiPo Shop 700r4 lockup

Now that I've converted from TPI to a carb I have to figure out the easiest kit to use to control the lockup on my 700r4 tranny. For those who may have done this swap already, how did you wire yours and what was the cost?

There are several kits out there & they vary in procedure. I get a vacuum switch from a late 80'S van (green & blue wires) & a choke pressure switch from a 70'S 6 cyl. Hook the vacuum hose to ported vacuum on the carb. Put the choke switch in the pipe plug outlet for 4th gear. Wire a fused wire from the ign circuit through the vacuum switch, through the choke switch & to the trans. connecter. That kicks the lock up in at part throttle in 4th gear. It releases at closed throttle or full throttle.
I suppose you have the cable hooked to the carb correctly. That is the most important part.

Robert I have the TH350C, pre-curser to the 700r4, B&M do this .
I too was looking for a similar solution.
It's a bit pricey though.

They also do an electronic speedo compatible one too.

the lockup is very easy to wire up. no kit is required 700R4 lockup wiring diagram

I like this option, looks real simple. Question is, how do I identify the pins? From what I've been told, when looking down from the top, the back left pin is hot.Is that right?

the colors at the bottom of the picture at the tranny connector is the factory colors. i have used that wiring for over 100,000 miles and the tranny still works like the day i got it. it had 150,000 miles on it when i bought it

This is a timely subject for me. I just finished installing a 700R4 and need to wire it. Not sure I follow the logic of the circuit though. If you delete the optional manual switch then Pin B and D are simply connected to an unswitched ground. It appears to me the only controlling input is the brake light and that would be used to unlock the converter. What other input am I missing?

its only locked up in overdrive and unlocks when you hit the brakes. that optional switch is for if you were towing or something in 3rd gear for a long time and you wanted the torque converter locked up to reduce heat

I'm not using the factory plug for the transmission, so which pin is hot? Also, is there any paticular why a 5 pin relay is used or will a 4 pin work just as well?

700 r4 plug pins looking at the pins on the wireing harness connector

need a 5 pin relay because you need normally closed contact. when you press the brakes, it kills 12v to the torque converter

the lighted switch is to turn it on or off. the lighted section will light when it goes in overdrive. i just leave the switch on all the time. it won't lock by itself until it shifts in overdrive.

Awesome! That's all I needed to know.

One more question. Do you have a part number or model number for the Bosch switch?

Thanks

i don't have a part number handy, but you can get the relay at any autoparts store

I've been looking for part number myself and found #RY115 from Car Quest.

Thanks for the info. This doesn't seem to be as complicated as I was concerned it would be.

Can a SM 420 (4spd be replaced with 700 r4? Will the 700r4 match up with out modification or some modification such as the lock up for 3rd gear? Is the bolt pattern close?

adapt to what engine?

316 pontiac engine , now have SM420(4spd)Can a 700r4 be matched/adapted to the 316 thanks

Anything is possible with enough time and money. I don't believe there is an easy bolt-on way to do what you want. You may need to make or have made your own tranny adapter.

Might want to try these guys.

http://www.transmissionadapters.com/early_pontiac.htm

$ 795.00 from that company for the adapter

Ouch. I'd next model the cost of making the conversion against spinning the motor faster. It may be you'll never drive it far enough to justify the cost of adapter and trans. Or maybe you'll drive it so much the decision is a no-brainer...

Thanks for info on adapter from Ham Lake MN.Bendtsen's transmission adapters. Looks very interesting may have to paythe price.

Ok, let me get this straight, no power to 87A when brakes applied which goes to pin A, Optional switch provides ground if towing in 3rd switch N.O., Ground provided to lighted switch when convertor locks up in fourth from internal ground/case? Also I'm running the Edelbrock 1406 Performer carb with a Lokar TV cable and bracket. I set the TV cable to full open at WOT at idle cable has slight tension roughly 3/8" from cable housing. Does this sound correct or has anyone run this set up? I did notice Bowtie Overdrives offer a different spring for the plunger at valve body and an adaptor for the throttle arm for the TV cable? Does all this need to be installed or will current configuration work? Thanks G

I did the same thing as wrenchbender-who needs a high dollar kit...

Good info glad i saw this before i orderd one of the other kits out there

Gentleman, I have used the wiring diagram that "complexvariable" shared with us. I have noticed that with the fused switch on my light is on wether it is running or not and it doesn't make any difference if it is in gear or not. The power feed to A terminal is killed through the brake switch but pin B is grounded at all times and pin D has a trace of ground. I checked the pins with my DVM and if you hook the negative to pin B and the positive to a power scource it will show battery voltage, pin D will show 4.5 vdc. I have also ohmed Pin D to the case and it shows continuity. I have not drove it yet but it starts fine and goes in and out of gear as it should. I thought pin B provided a ground at lock up? Can anyone straighten out my fried brain? Thanks G

your transmission might be wired differently or a wiring problem internally.

Hmmmm guess I could separate pins B & D and see what happens or pull the pan and trace the wiring. I'm just concerned it would be in lock up all the time. I'm not having much luck finding the info I need. Thanks G

Update: I pulled the pan, the 4th gear switch was n/c single pole and opened under pressure, the 4-3 switch n/o dual pole. Bingo! I used a n/o dual pole in the 4th gear lock up port. Problem fixed and it works.

good to hear