I have done a days worth of research before posting this (use the search button, it's great!) and I found a bunch of ways to lock up a 700r4 depending on the age and configuration of the tranny. My model number seems to be missing or ground off so I took the pan off to see what the configuration looks like... and I am pleased (I think).

The most reliable kit I found on line was from Painless Wiring and was basically a 12 Volt series circuit with vacuum and brake fail safe switches and a 2 wire solenoid to lock up the torque converter after the circuit gets ground through the 4th gear pressure switch. Nice kit, although a bit pricey.

When I look at the guts of the tranny (picture attached) it looks like everything is already there. It even has the 2 wire solenoid and 4th gear pressure switch and my observation is that all I need is the vacuum switch and dual break switches and some wire. Am I missing something???

Thanks
Chuck

Here is a larger photo. It looks like an easy hook up.

http://img336.rockyou.com/imagehost/15/15625/15625525/15625525_dc5517ce1245559952.jpg

Thanks
Chuck

You have a nice later 700 transmission (87-92), you are correct, that is the 4th gear switch (single prong, normally open). The only thing you might want to change, is eliminate the other sensor, which is the temp sensor originally use to let the ECM know that it is warm enough to allow lockup to work. Basically have the red wire from the solenoid go directly to the "A" terminal of the lockup plug and the black wire goes directly to the 4th clutch switch, once it goes to 4th gear, the switch will close and send the ground to the lockup solenoid. I've used the painless kit before myself on a few vehicles, the only problem that I don't like is that 4th gear and lockup usually happen at the same time, and kind of lug the engine. With the vacuum switch, it will kick out of lockup when you push down on the gas which lowers engine vacuum. The switch opens at 7 lbs of vacuum or lower. Also the convertor will unlock when you push the brake pedal, or when the transmission downshifts from 4th to 3rd.

Thanks Jim,
Here is a drawing of the tranny wiring and my version of the external kit. It would be easy to bypass the thermal switch by just externally jumping the black and light brown wires to bypass the thermal switch. The external stuff has the brake switch and vacuum switch and I can get the connector from a surplus place for next to nothing. I bet I can do the entire kit for $50 bucks. I wouldn't use a manual lock up.

I am guessing that I wouldn't need to change anything internally???

Will the vacuum switch keep the tranny from locking up immediately when it goes into 4th under normal driving conditions?

Thanks
Chuck

It would only delay lockup at higher throttle ranges when the engine is only producing 7lbs of vacuum or less. If you are just cruising around at light throttle, then the lockup is going to come in pretty much on top of 4th gear. On my 66 with a 454 and a 700, I am running the B&M lockup system. It uses a speed sensor in the speedometer cable underneath the car at the transmission, and has an adjustment knob inside the vehicle, and you rotate the knob for higher lockup speeds.http://www.bmracing.com/PRODUCTS/Transmission-Accessories-and-Kits/Converter-Lockup-Control-for-GM-automatic-trans-w-lockup-converter-mechanical-speedometer

Interesting, thanks Jim! I think I will add a kill switch in line with the +12 Volts, just in case. I really see no need for the optional lock up switch.

The male tranny connector is a "WP64". I think I will just build my own kit. All I need is a switch, a vacuum switch and the brake switch. I can't imagine that will cost $100.00.

Thanks
Chuck

Chuck, the OEM part# for the vacuum switch that comes in the painless kit is 14014519, which should still be available from your local GM dealer. This same switch was used on most GM pickups with a lockup torque convertor from around 80 to 85. The only problem I had was trying to find the correct electrical connector to plug into the vacuum switch. Another thing you could do while driving your vehicle, is to just leave it in 3rd gear until you get out on the highway, then shift into 4th, since it won't go into lockup in 3rd anyway.

You have a nice later 700 transmission (87-92), you are correct, that is the 4th gear switch (single prong, normally open). The only thing you might want to change, is eliminate the other sensor, which is the temp sensor originally use to let the ECM know that it is warm enough to allow lockup to work. Basically have the red wire from the solenoid go directly to the "A" terminal of the lockup plug and the black wire goes directly to the 4th clutch switch, once it goes to 4th gear, the switch will close and send the ground to the lockup solenoid. I've used the painless kit before myself on a few vehicles, the only problem that I don't like is that 4th gear and lockup usually happen at the same time, and kind of lug the engine. With the vacuum switch, it will kick out of lockup when you push down on the gas which lowers engine vacuum. The switch opens at 7 lbs of vacuum or lower. Also the converter will unlock when you push the brake pedal, or when the transmission downshifts from 4th to 3rd.

Jim, I found the vacuum switch at Summit and it's $45.00. The brake switch is $15 and the connector is $5. Seems easy to do it for about $70.00.

Why wouldn't I want to leave the thermal switch in the circuit? As it stands the thermal switch is in series with the 4th gear pressure switch to ground so it won't lock up until it's warm. Not a bad concept.

Thanks
Chuck

Jim, I found the vacuum switch at Summit and it's $45.00. The brake switch is $15 and the connector is $5. Seems easy to do it for about $70.00.

Why wouldn't I want to leave the thermal switch in the circuit? As it stands the thermal switch is in series with the 4th gear pressure switch to ground so it won't lock up until it's warm. Not a bad concept.

Thanks
Chuck

Chuck, I was thinking only for simplicity. You could leave it in, but I don't think it would work like you think it would. The thermal switch was designed only to tell the ECM that the trans is a certain temp on the "B" terminal. Look at your schematic, the black or "D" terminal wire doesn't go through the thermal switch to prevent lockup. Once the ECM sees the correct temp through the "B" terminal, it sends the ground back through the "D" terminal back to the solenoid. I have tested these thermal switches at different temps, and have never got one to actually close completely no matter how warm you get it. Jim

I spent about $25 at Radio Shack and built my own lockup circuit. It locks up when I push the lockup button, and unlocks when I tap the brakes. It will lock in any gear anytime I want it locked.

Chuck,

You've got this figured out! The parts you need for inside the tranny are all there. I have done two lockups, and left the temp sensor out in both. The drawing you have is right on.

For outside the trans, all you need is the brake switch. It is common to many GM vehicles. You can live without the manual switch and the vac switch.

I have done the swap for free, by getting the switch from a donor vehicle!

Chuck,

You've got this figured out! The parts you need for inside the tranny are all there. I have done two lockups, and left the temp sensor out in both. The drawing you have is right on.

For outside the trans, all you need is the brake switch. It is common to many GM vehicles. You can live without the manual switch and the vac switch.

I have done the swap for free, by getting the switch from a donor vehicle!

Great input Zeke and Jim. Zeke, my only concern with not using the vacuum switch is that it will stay locked up when climbing a hill or some other load, right? If it down shifts it will unlock, but is it bad to be under load in 4th and locked up? That's the only reason I would spend the $45.00 on the vacuum switch. If I don't need the vacuum switch, I am ready to go, on the cheap.

I definitely don't want a manual lock up though.

Thanks
Chuck

I haven't had a problem with mine. On a ling gentle hill, were you want very gentle acceleration that requires torque converter action but no downshift, you may feel it (it will chatter slightly). Easy enough to manually shift or get on it a little harder and cause a downshift. On a decent hill, it will downshift anyway.

The vac switch would be very nice. But $45 is a lot. If it were mine, I'd go without for starters and then keep my eyes open at the U-pick for a switch and harness connector. I might add one to mine if I run across a donor.

I haven't had a problem with mine. On a ling gentle hill, were you want very gentle acceleration that requires torque converter action but no downshift, you may feel it (it will chatter slightly). Easy enough to manually shift or get on it a little harder and cause a downshift. On a decent hill, it will downshift anyway.

The vac switch would be very nice. But $45 is a lot. If it were mine, I'd go without for starters and then keep my eyes open at the U-pick for a switch and harness connector. I might add one to mine if I run across a donor.

Actually I was thinking just that Zeke. I was going to wire a loop into the engine compartment that I could cut if I got a vacuum switch or it didn't act the way I wanted it to.

Thanks
Chuck

We are just about ready to install the trannys. My friend and I both bought 700r4s but he got the older one with no pressure switch. I have looked on line but can't find one. It is a n/o switch that screws into the 4th gear slot to lock up when the car goes into 4th gear. Anyone know where to get one?

His early tranny was just rebuild. I assume it will be OK behind a 350 hp 350.

Thanks
Chuck

You can get the vac. switch at the salvage yard. Early to mid 80's cars & trucks had LU converters. Then you can get the delay valve that goes with it too.
On trucks it's mounted on the firewall by the brake booster.

Thanks Jim, We are looking for the 4th gear pressure switch, not the vacuum switch.

Chuck

Someone told me about a lock up delay switch that goes on the outside of the older trannys. He's not sure about the later versions. It will delayy the lock up hydraulically. It screws into a port in the side of the tranny. If the tranny goes into 4th at, say 35 MPH, the delay makes it lock up at 45 and eliminates chatter associated with simultanious 4th gear shift and lock up.

Anyone have any info on this? If you can find it, I can wire it.

Thanks
Chuck

Somewhat off-topic but still applicable:

I used an aftermarket kit (TCI, I think) to control the lock-up on a 700 installed in a '75 Nova.

The vacuum switch supplied in the kit had no hysterisis. So the converter clutch would lock up, engine vacuum would drop, converter clutch would unlock. Then the vacuum went up, so it'd start all over. The switch was adjustable--but it only changed the vacuum level that engaged/disengaged the switch. (So I could have problems at any vacuum level I chose...)

Put a delay valve in the vacuum plumbing to the vacuum switch to prevent the switch from rapid cycling.

I strongly recommend the use of a vacuum switch, and an adjustable one if you can get one. But the clutch cycling drove me crazy; and I wasn't smart enough to install the delay valve in the vacuum hose.

My 700r4 doesn't lock up in 4th. I can easily fix it but, am I in any jeopardy by driving it unlocked until I get time to remove the pan? It is a 4th gear only lock up (late model).

Thanks
Chuck

Fix it,
It has reduced lube flow in 4th with the converter not locked. You can drive it around but stay out of 4th and off the highway.

My 700r4 doesn't lock up in 4th. I can easily fix it but, am I in any jeopardy by driving it unlocked until I get time to remove the pan? It is a 4th gear only lock up (late model).

Thanks
Chuck

Good question there. What is the white plug for on side of the 700r4. Mine is a 87 700r4. original trans in a caprice. But after I swap the engine in it I made a mistake and cut the wires that go to that plug. I still have the plug and about 2ft of wire still connected to the plug but I dont know what the wires hook up to. I been driving the car like that for about 2 yrs now without the little white plug plugged into the tranny. BTW, All interstate driving too. How would I know when my converter is locked up and not.:confused: car goes in 4th no problems and downshift to 3rd when needed and back to 4th. Could someone please tell me the purpose of the plug and what should I wire it to if I need it.

Good question there. What is the white plug for on side of the 700r4. Mine is a 87 700r4. original trans in a caprice. But after I swap the engine in it I made a mistake and cut the wires that go to that plug. I still have the plug and about 2ft of wire still connected to the plug but I dont know what the wires hook up to. I been driving the car like that for about 2 yrs now without the little white plug plugged into the tranny. BTW, All interstate driving too. How would I know when my converter is locked up and not.:confused: car goes in 4th no problems and downshift to 3rd when needed and back to 4th. Could someone please tell me the purpose of the plug and what should I wire it to if I need it.

I always encourage people to read the entire thread. Go back one page on this thread and you will see a schematic I created for hook up of the lock up system. Good luck.

Chuck

Fix it,
It has reduced lube flow in 4th with the converter not locked. You can drive it around but stay out of 4th and off the highway.

I took it out with the manual lock up wire in my hand to see if I could feel the difference. I grounded the wire and no difference at all, and I confirmed that the wire does pull the solenoid.

I ran it at 65 MPH and then let it drop down to 50 and I tapped the brake. I could immediately hear it drop out of lock so it works just fine. The reason I didn't get a response from grounding the manual lock up wire was that it was already locked.

I have heard so many stories about how it lugs down in lock and that you can feel it lock up. I can't tell at all. It's smooth as glass and drops right out when it's supposed to, Jake.

Now if it only would go into 4th at 55 or 60 instead of 45 MPH I'd be real happy. When I change from 3.31 to 3.55 gears next week I suspect it will shift into 4th even lower.

Thanks for all the help buddy.
Chuck

just wondering for the manual switch , if you put a shift light set up there so you could change the rpm were the coverter locks up . say you set it at 1700 rpm the light comes on converter locks ,it drops below 1700 it unlocks . sounds like it would work with a relay and a bit of solder .

just wondering for the manual switch , if you put a shift light set up there so you could change the rpm were the coverter locks up . say you set it at 1700 rpm the light comes on converter locks ,it drops below 1700 it unlocks . sounds like it would work with a relay and a bit of solder .

It would. Take the ouput of the tach and fire a relay rather that the shift light and set it to pull the relay at a certain rpm. The danger is that you may go into 4th at 50 and not lock up until 60, not good. That only changes the lock up, not the shift to 4th.

Jake, what do you think? Is there and easy way to delay the 3/4 shift to about 55?

Chuck

Jake, everything works great and it does lock up OK.

It still shifts into 4th at 45 mph and I think it will be worse when I go from 3.31 to 3.55 gears this weekend. Is there a way to have it delay the 3/4 shift until about 55 or so (a way that a mere mortal like me can implement)?

Thanks
Chuck

If you tighten up the TV then it shifts too hard for your taste?

If you tighten up the TV then it shifts too hard for your taste?

I don't understand your question. If it is too tight then it shifts late.... but late in all gears. I just want to delay the 3/4 shift.

Thanks
Chuck

Yes,
3-4 shift can be delayed by installing a stiffer 3-4 shift valve spring. Usually this would be a real PITA but the TransGo repgroamming kit comes with an orange spring for this purpose and they advise installing it in vehicles with 3.73 or deeper gears.

I usually don't install the spring because it makes it a bit too late.

So,
you can shim the existing spring with a ..050-.060" washer of the proper diameter or I can round up one of the leftover TransGo springs.

Is this something I can do without screwing something up?

Thanks
CB

I bringing this thread back, because it answered just about all of my questions. Thank you.

But to confirm, since I have a 92 trans, it will lock in 3 & 4, automatically with power to the solenoid?

Great thread...maybe it should be made a sticky? A related question...
Anybody know of a good source for the vacuum delay switch..besides junk yards? I have found part numbers for the following

GM part# 14020691 --- Discontinued
ACDelco # 214-479 --- Discontinued
Standard # DSV35 ---- No one stocks and haven't been able to find on-line
BWD #EC342 - Special order only - can get from Pep Boys in a week they claim - cost is about $6.00 Not really sure if it has the correct function or not.

I have the TCI lockup kit and have the earlier described-'surging-lockup' problem and want to try the vacuum delay switch, before going to one of the methods described, as it's a simple cure and quickly doable and reversible if I don't like the results.

Great thread...maybe it should be made a sticky? A related question...
Anybody know of a good source for the vacuum delay switch..besides junk yards? I have found part numbers for the following

GM part# 14020691 --- Discontinued
ACDelco # 214-479 --- Discontinued
Standard # DSV35 ---- No one stocks and haven't been able to find on-line
BWD #EC342 - Special order only - can get from Pep Boys in a week they claim - cost is about $6.00 Not really sure if it has the correct function or not.

I have the TCI lockup kit and have the earlier described-'surging-lockup' problem and want to try the vacuum delay switch, before going to one of the methods described, as it's a simple cure and quickly doable and reversible if I don't like the results.


UPDATED Info...

GM part# 14020691 --- Discontinued
ACDelco # 214-479 --- Discontinued
Standard # DSV35 ---- No one stocks and haven't been able to find on-line
BWD #EC342 --- No longer available from manufacturer


Anybody got any ideas on the specs on these or a part # of one that will work? Maybe there is something out there that is a close match in function. Thx