I've had lots of guys asking me how to wire the 700R4 so the TCC will work. I found a site that will help. I hope this does you guys some good. http://www.tciauto.com/Products/Instructions/instructions/376600_inst.htm
Bump. Got a 700R4 out of an '83 Chev that works great but as far as I can tell the converter doesn't lock up. No wiring at this point. The old connector at the trans has four pins with only two being used, the front inside had a blue wire and front outside a green wire. Is it really supposed to lock up with no wiring? Can I apply 12v to one of these wires while going down the highway to test for lockup?
It will NOT lock up with no wiring. You need a 12v source (keyed, IGN) and a ground. From the 4-pin connector a wire goes through a pressure switch on 4th gear, through the TCC solenoind, and off to ground, at minimum. Some wire through a switch piggybacked on the brake lights, to unlock when you hit the brakes. Others use a toggle. Some throw a vacuum switch in the mix. It's all good. Either way, it will only lock in 4th (although GM did have some models that locked in 3rd as well). Yes, you can apply 12V to test the lockup, but do not depend on the case for ground. Run a test ground to the plug, too.
Gimpy, sorry I hadn't noticed you replied to my post. I have tried 12v and grounds to the terminals I thought should make it work but no luck, so today I pulled the pan to make sure the guts were there. Also didn't know there were 3 wires running to the connector, not 2. Hoping you (or anyone) can give me an idea of which wires need power and grounding. I can figure out the brake disconnect etc. once I get it to lock up. I believe the trans to be out of an '83 diesel pickup but can't be positive.
Oooh, sorry, I lost track of this. Never hesitate to contact me directly. Also, you can always tag me in a post. Just type @ before my username, like @blowby and it will let me know that I have been tagged. It looks like you may have one that is capable of locking up in 3rd, too. Many diesels had that. If you compare your picture to this one: You will see that you have an additional switch that is not shown above. That additional pressure switch is on 3rd gear. Shown here (earlier 700R4, without aux. valve body): The quick-and-dirty wiring is: 12V (IGN on) from the bulkhead connector by the pan rail to the not black lead on the TCC solenoid. Run the ground from the TCC solenoid to the 4th pressure switch. It grounds when there is pressure (when you are in 4th.). If you want a manual override, you can put a switch in the 12V (IGN on lead). A double-pole double throw GM brake light switch has a second pair of spade connectors on it, to interrupt that current, and unlock the converter when you apply the brakes. Some kits have vacuum switches to do this, too. Some have both. If you want to get all fan see, you can wire the 12V (IGN on) through the 3rd pressure switch first, and then off to the TCC solenoid. Then you'd have lockup in 3rd and 4th. If you have a high torque engine, or a light car, this could work well. The third wire is an ECM (or in the case of a GM diesel PCM) feedback wire, or a lockup light for earlier models. The remainder are 12+ and ground. There are several variations on the theme about how power and ground are delivered to the TCC solenoid. Some people use a two-pole 4th gear pressure switch, and use manual, vacuum, or brake light switches (or some/all of those) to provide ground to the solenoid. You'd have to have a 2-pole 4th gear pressure switch for that. It appears that you have a single pole pressure switch. If not, let me know. Yo do know that you will need to change the torque converter and governor, right? The torque converter on a diesel has a very low stall speed compared to a gas one. The governor is set up for low RPM, too.
Gimpy you are the man! I just got back from the local tranny shop. The guy was busy and couldn't help me much but he did say something about making sure it locks up in 3rd which floods some area with fluid, otherwise it will burn itself out? Make any sense? What is the dingus next to my 3rd gear switch, the one the wires from the bulkhead are running to? I don't see it on the early drawing you posted. He also said something about an overheat switch... Yeah, I have been driving this (not on the highway yet) with a fairly anemic SBC. The converter is not too bad but the early shifts need attention. I meant to buy another governor at Pick and Pull on Memorial weekend but got caught up in the half price sale, bought a bunch of other crap and forgot. Shouldn't be hard to find a gas engine one. The converter I will have to live with until either the engine or trans come out again.
Here is the way it is wired now, laying on my back from the driver's side. How much of this can I leave alone?
There is a ton of info on the 700r4 torque converter lockup out there. Here are a couple to get you started: http://www.rowand.net/Shop/Tech/LockupTCCWiring.htm http://www.chevelles.com/forums/33-transmission-driveline/131200-700r4-question.html I think the simplest possible manual TCC control would be grounding B and D and supplying +12V to A with a toggle switch.
Leave it. Yes, that's an overheat switch. I have yet to figure out what they do exactly. Otherwise, it looks good.
Argh, I still don't get it. Here is the wiring with the overheat switch out of the picture. Terminal D (outside rear) goes direct to the solenoid, which means something has to be hooked to it (ground?), no? None of the aftermarket wiring kits or diagrams use this terminal. Terminal B, which goes to the 4th pressure switch is supposed to be grounded, but I don't see how that would do anything since it's a one wire switch. Maybe someone messed with the wiring in this thing before I got it but it sure looks untouched.
The TCC solenoid may be bad. If you have the pan off again, try applying 12V to it and see if it reacts.
Houston, we have lockup! Not to drag this O/T thread any further but a few observations I learned along the way may help others. 1. My TCC solenoid was bad, caused by me wiring it backwards in my initial attempts. They are polarity sensitive, be careful. 2. There are about 100 variations of lockup designs for these transmissions. I had to ground the D terminal as my diagram above indicates. The B terminal is used for ECM feedback or some such on mine. 3. My trans is designed to lockup in 2,3 and 4. I believe the 2 and 3 lockups were eliminated in later transmissions. So if you get one it really helps to know the year and what it came out of, and have the wiring diagram. If not pull the pan and find a diagram that matches the internal wiring. Thanks Gimpy and David for the help.
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