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Painless Co. 700R4 Tranny Lock-up Kit

PJ Walters

PJ Walters

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Good Morning CK5, it is a beautiful day just waiting for us to bust some knuckles on rusty bolts while rolling around in burned up motor oil. HA! Anyway, since we got the temp situation worked out on my 89 K5 I am on to another issue. During by build I decided that I did not like the 80's TBI and I yanked the original ECM out of the truck. Everything worked out great except when I got to my tranny wiring. From what I was told, the original ECM controlled the 4th gear lock up. Since my ECM was now somewhere in Cumberland County Landfill, I needed to find a solution. I ordered Painless Product 60109 TC Lock-up kit. Kit was easy to install and was done in a matter of an hour or so. I took my first test drive and when it came time for the 4th gear lock up it would engage and disengage resulting in what I would describe as a bucking bronco on crack. So I checked out the installation guide and it said that some people would have this issue. So they tell me to buy a vacuum valve from Standard Ignition #DSV31 and that that will correct the vacuum issue causing the constant engage/disengage. Well I cannot find the preferred Standard Ignition as it appears that they do not make that product any longer (If someone has it, HOLLER!). So I call Painless and they tell me to buy a Dorman 47149 check valve. So I did. The valve arrived and I could literally blow through both ends. I call Dorman and they say that is normal and the the valve is good. To me it actually looks like a reducer as one stem is much larger than the other stem. Anyway, I installed it and it did make it work a little better but I still have a slight engage and disengage at a certain RPMS. Has anyone else had this issue? There is an adjustment screw in the vacuum switch itself and I think I have to turn it counterclockwise to allow for a little more vacuum (that statement is speculation and if I am wrong correct me please).
 
Help me understand. This vacuum valve is on the brake switch?
In my non computer 700r4, I went with Bowtie Over Drive lock up kit. It is all electric. When 4th it locks and stays locked.
 
The way I understand the system works... through the vacuum off the manifold. There is a vac tube from the bottom of the Sniper that runs to a vacuum switch. The switch has an Acc hotwire running to it and a TC lockup wire running out to the tranny harness. Once the appropriate vacuum is reached it switches on the lockup. When it locks in, it should stay locked in. The disengage is on the brake peddle. So when you brake it comes out of lockup. Apparently Painless is aware of this problem as they suggest various valves to solve it. That is where I am currently at. The link to the manual is below. https://www.painlessperformance.com/Manuals/60109.pdf
 
So does the sniper need to know if in lock up. I don't understand the need for the vacuum switch.
You could use a double terminal electric brake switch and eliminate the vacuum stuff.
 
Nope. The Sniper doesn't care or read anything on the tranny. It simply has the vacuum port like a normal carb would have. So in my defense. I have only built manuals. My first three trucks had SM465 trannys and this auto stuff is very new to me. Are you telling me there is a better way? If so, bring it on. please. haha
 
Your particular kit is discontinued. However, I see the electrical "trigger" instead of the vacuum. I think I looked at this option from the go, but I couldn't find an electrical unit that didn't rely on an in-line switch to be used manually.
 
I think only the ac Delco brake switch is discontinued. Should be able to find it aftermarket.
The manual switch in that set up is for 3rd gear and brake switch still unlocks 3rd with it manual in lock up.
 
That means I will have to go back into the pan, a job that ranks pretty low on my suck list. So I see the beneficial part of having it in lock up as much as possible... I wish I knew this before I dropped money on this system. I have an email into Painless to see what they suggest. If I cannot get this thing up to par I will go the way of your design. BTW they have a new design that basically works like yours except off of functioning break lights. https://www.bowtieoverdrives.com/catalog/catalog_inc/viewitem.php?ITEMID=336
 
So try this by pass the vac switch on the Painless system.
Idk how much this trans has been driven since mods. Make sure he TV cable is adjusted properly, if it is not adjusted correctly it will damage the clutches.
But I think Painless over complicated their kit. Early 700r4's had a vacuum switch, but later years didn't.
Aside from the vacuum switch the diagram looks the same as the 4th gear auto lock up.
On your test drive once you get into 4th, if you rest your foot on the brake the engine rpm should raise @ 200 rpm when tc unlocks
 
Your kit came with the switch Bowtie says they can't get anymore. So if you jumper past the vac switch it looks the same as mine w/o the optional manual switch for 3rd gear
 
It should only engage in 4th. Painless doesn't explain the purpose of the vacuum switch. As long as the tc only locks in 4th gear it doesn't matter what speed. ideal it will be 40-42 mph, mine will go into od as low as 36 mph.
 
I've seen kits with an external pressure switch. It threads into the 4th gear test port. That might be the way to go until you're sure that's the method you want.

I would try to find a factory vacuum switch and a factory delay valve and try that out. The factory pre-ECM-controlled setup worked pretty well, but it also had another valve in the valve body based on governor and TV.
 
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As you can see the lockup wiring for the 700 is stupid simple. All it is a switched hot source to engage and disengage the lockup solenoid.

Originally the wiring on my 72 k10 was setup so the converter was constant hot (always locked). Really terrible way to have it setup.

Here’s what I did: I used a TCI vacuum switch and a delay relay timer switch to control the lockup. The hot side runs through the vacuum switch in series with the timer relay. A person could run it without the timer but having the converter immediately lockup as soon as vacuum comes back is not ideal. It just don’t drive good. Lol. Without a timer, it wouldn’t allow you to make a pass and allow the engine to get back to a comfortable rpm and load prior to relocking without the timer. The result would be consistent lock and unlock. Lastly, the hot to the trans should be shorted when the brake pedal is pushed. If you look at the brake light switch, it is opposing in that one side will always be hot when depressed the the other side won’t and visa versa in that regard. So wire the entire thing in series with the constant hot side of the brake switch.

The setup works perfect. The converter will unlock when under low vacuum conditions (high load) and will only relock when the engine is no longer under a high load. Additionally, because the timer is in series about 4 seconds has to elapse prior to relock. Again, allowing the engine to settle in at the new speed prior to locking again.

The vacuum switch and timer are adjustable so you can set appropriate to your setup. A small amount of trial and error and once dialed in, works very much like the stock system. If my memory serves me right the vacuum switch was adjustable from about 0Hg to 15Hg. And the timer is adjustable from 0 seconds to 12 seconds.

Once the setup is installed, lock up occurs immediately once the trans shifts into 4th. The converter only unlocks when passing.

Both switches together cost about $40, a few bucks in wire and there you go!

Sorry I can’t help you with the painless kit you have there. I did look it up and appears to be the exact same switch that my tci switch is. ….Probably the same Chinese factory. Anyways, if you turn the screw in, it should take less vacuum to disengage. If you turn the screw out, it will take more vacuum to switch. Based off what you described, I would turn the screw in so the converter will only unlock under low vacuum conditions. This is assuming there are no shorts anywhere and that’s not causing the constant lock and unlock. Before adjusting the vacuum switch, turn the key forward to the on position and check for hot power at the transmission. It should be hot all the time until the vacuum drops or the brake pedal is pressed.
 
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K5er4Life said:
I used a TCI vacuum switch and a delay relay timer switch to control the lockup.
Click to expand...
The factory setup uses a delay valve, like I mentioned above, to solve this problem. It's near the bottom of the label. There is a little filter or restrictor, plus the "DELAY VLV" in series with the vac switch.


K5er4Life said:
astly, the hot to the trans should be shorted when the brake pedal is pushed.
Click to expand...
No, it should open, not short. The term you're looking for is "Normally Closed".

20210914_065733.jpg
 
Definitely resurrecting an old thread.... But I am running into the exact same issue with a very similar setup. Running a sniper with the painless lockup switch as well. I purchased the same check valve you have mention and it did definitely help but still does it occasionally although not nearly as bad. Where you able to "tune it out" by messing with the adjustment screw? Or did you come up with some other method?
 
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