700r4 lockup help
 

Swapped the quadrajet for an edelbrock, realized pretty quickly that the lockup was now non-functional so I read a ton online and still have trouble. Bought a kit from superior transmission, consisting of an oil temperature switch and some wires. Instructions don't really address a non-computerized vehicle. Installed in the 4th gear pressure port, ran wire to A terminal on transmission plug, other wire from oil pressure switch to a dash switch. Other two wires I first cut off and connected to each other, blew a fuse at switch so I then ran one of them (D) to ground. Stopped blowing the fuse at least, test drive and lockup worked right at first but then reverted back to not working and heating up the transmission. If I understand correctly, I am sending 12+to temp switch, when pressure closes the switch I'm sending 12+ to A terminal and thus to solenoid inside to cause lockup. But some of info I've read indicates it should ground the solenoid.
I am trying to do this as simply as possible, without a vacuum switch and without going through the brake light switch. If anyone can help me, I'd greatly appreciate it.
It's a 1986 GMC K25 350 with a supposedly 'built' 700r4, worked flawlessly before I messed with the carburetor.
Thank you.
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Re: 700r4 lockup help
 

you need to read the "700R4 Build Thread" on here......Once you speed read thru that thread you will be able to fix your issues

Ok will do. I started reading it but saw only stuff about modifying internal parts and mechanical stuff. I'll look at it again. Thanks
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Re: 700r4 lockup help
 

Re: 700r4 lockup help
 

Read all of that, didn't see much regarding tcc wiring. Supposedly it's possible to externally wire it to work from a switch
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Re: 700r4 lockup help
 

If it worked before you changed the carb, why would you re-wire anything and add a switch ? It is a 1986 right ?

The old quadrajet had tons of vacuum lines that aren't needed for the edelbrock, as well as a bunch of wires, some that weren't being used, so I hooked up the edelbrock with vacuum for brakes and vacuum advance, quickly realized I had bypassed the vacuum switch for the tcc. Tried running vacuum to it but it didn't work, idk what the rest of the carb wiring went to or where to try to run it. So I figured since people have been putting 700r4s into carbureted hotrods for 30 years, there should be some simple manner to power up the solenoid. I bought a simple kit from Superior transmissions but the instructions only seem to apply to computerized cars.
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Re: 700r4 lockup help
 

Do you want to run a manual switch or vacuum controlled lockup kit? I have one wired to a toggle switch so I can control it to lock up when I want, it was a temp fix since my computer ('87 GMC) wouldn't control the lockup and I was driving across the country. I have since swapped it from TBI to carb and retained the toggle switch for the lockup. Works fine, though there are plenty of people who say it's a bad idea due to panic stopping etc. I've never had an issue.
Couple different companies make vacuum controlled lockup kits, basically same operation as a toggle except the vacuum switch opens or closes the circuit. Either way sends 12 volts to the trans when the switch is closed. TCI is one company that comes to mind.
I don't remember the position of the wires on the 4 pin connector on the trans. A may be 12V and B ground, but double check that.

That's what I need to find out. I'm trying to avoid using a vacuum switch or brake light switch. Not worried about being locked up and slowing down, it only works in 4th and it downshifts pretty easily with 4:56s.
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Re: 700r4 lockup help
 

What year is your transmission?

You can use a hydraulic lockup kit if there is a bore in the valve body for the valve.
Superior, Fairbanks, Transgo offer them. I used them it works fine. No electricity needed.

http://worldwidepartsoutlet.com/worl...onic%20TCC.jpg

Idk what year it is, or how to tell. Trucks an 86, originally came with a 700, I know it was rebuilt but idknifnit was swapped with a different year. So if it's a certain year, do I need to do a hydraulic kit? Or will my electric kit work?
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Re: 700r4 lockup help
 

just wire it to the 4th gear oil.....battery and ground...you done. so when trans achieves 4th gear it will apply the TCC thru the solenoid....town driving might be a *****. meaning achieving TC apply to early in town driving is all.....good luck!!!!!

Ok now we're getting somewhere. I have the pressure switch in the 4th gear port. I have 12v from a toggle switch to one side of the pressure switch. Other side goes to "A" terminal on trans pigtail. First attempt I cut off and tied the B and D wire together. Blew inline due to toggle switch. Then undid B and D, ran D to a ground. Worked perfectly one time, then back to square one. Not blowing the fuse now, however. So I've tried both options that I read about with B and D. Any other suggestions for B and D? Am I correct with my positive wires?
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Re: 700r4 lockup help
 

again, you need to read the thread "700r4 build thread"......It would be to easy for me to just give you the answer.....LOL!!!!!!!! You must of skipped over post number 134 of the 700R4 build thread.....read it again, your answer will be in the nice big picture provided in that post number 134. don't thank me, thank the dude who put the 700r4 thread together...

Re: 700r4 lockup help
 

Ok so none of the posts are numbered, at least as I can see it on a smartphone. I reread several pages, found a couple diagrams that both show wiring thru the tcc solenoid. If I'm not mistaken, that's internal and I'm trying to do it external, which I thought was possible to do. My kit instructions said it can be done internal or external, but their instructions appear to be for computerized cars. I know people put 700s into hotrods with no computer. I don't want to use a vacuum switch, and I'm not real concerned about the brake switch as it will unlock when it downshifts anyway. And with 4:56s it downshifts pretty quickly.
One diagram showed the pressure switch grounded out. Which I don't understand at all. How's that going to take power from the toggle switch and send it anywhere?
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Re: 700r4 lockup help
 

Since you switched the carb, are you certain that your TV cable has the correct geometry and that your pressures are correct after the carb swap?

Not 100%, I've adjusted it a couple times to try to get it as good as I can. I'm going to buy the aftermarket bracket to move the back end of it to try to make it better. But that's been in the back of my head too
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Re: 700r4 lockup help
 

The reason I asked about the year is the wiring on the valve body is different between non computer and ecm controlled. This is an likely example of the wiring on a carbed '86

http://www.rowand.net/Shop/Tech/imag...gDiagram01.jpg

modifications really need to be done to run a toggle switch.

This is the schematic for a computer controlled tcc

http://www.austinthirdgen.org/mkport...8_vinE_TCC.jpg

power into A and ground on D should turn the solenoid on.

Re: 700r4 lockup help
 

Bowtie Overdrives makes the best TV cable correction kit.

Re: 700r4 lockup help
 

So are you staying I cant just wire it to work externally? I didn't change anything internally, I interrupted the factory vacuum switch and whatever else sends a signal to that solenoid.
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Re: 700r4 lockup help
 

Do what Capt. Fab suggests on the Bowtie Overdrive stuff. If you don't have the right geometry on the carb linkage for the TV cable you'll never get it to work properly and could possibly trash your transmission.

So all was good before you switched from a Q-jet to the Edelbrock? If so, wouldn't that be the "smoking gun"? TV cable adjusted properly?

Just some random thoughts from an old guy that I've learned the hard way...

Randy

i have adjusted the tv cable theee times and I feel like I have it where it should work right, but I'm still using the factory linkage bracket. So I just picked up an aftermarket adjustable linkage bracket, hopefully get a chance to throw that in tonight. I did check the solenoid. T putting 12v to the A wire while under there, I did hear a click. Couldn't duplicate it, I guess it doesn't disengage electrically?
The smoking gun was changing to a non-smog carburetor without properly addressing the tcc in the first place. When I realized it I tried putting manifold vacuum to the vacuum switch but couldn't make it work. And the rest of the original wiring was a mess, idk where the factory tcc wiring even went. So we'll see if the new bracket makes a difference.
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Re: 700r4 lockup help
 

DanSaco, maybe I missed something above so correct me if I did.

You're asking about converter lockup/unlock NOT kickdown (i.e. shifting from 4th down to 3rd), right?

First, my understanding is that cable adjustment doesn't control lockup. It IS critical, as others have noted and you may have known already, to proper control of the internal pressures and shifting.

Just to clarify, when you say "factory linkage bracket" are you referring to the linkage on the side of the carburetor? Forgive me if you already know but I ask because some people think the bracket holding the tv cable is what needs changing (from one of your posts: "Not 100%, I've adjusted it a couple times to try to get it as good as I can. I'm going to buy the aftermarket bracket to move the back end of it to try to make it better. But that's been in the back of my head too") but, in fact, it is the one on the side of the carb. the Edelbrock geometry isn't correct and you can't properly adjust the cable without fixing it.

I believe the Bowtie kit will require you to pull the pan to install a spring, mine did. Maybe they sell just the geometry corrector. other sources do

Don't know exactly what you did to test it when you hooked manifold vacuum to it but the way the vacuum switch operates is to unlock the converter when vacuum drops during rapid throttle application by breaking the electrical circuit to the converter.