HEllo, I have an 85 iroc tpi 350 with a 700 r4. The Torque converter clutch engages and disengages in every gear except 1st. I will just be driving in town doing about 30 and it shakes and stumbles. I slightly apply the brakes and it goes away. I had the trans rebuilt with a shift kit because of the trans slipping and it blowing the gauge fuse. I am beginning to think it is the wiring inside the tranny or car. Any one have a schematic or any idea about my problem??? THanks

 

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Does it seem like it is staying locked when it should be unlocked? If you hit the brake, then go part throttle, does the tach jump way up like it would when the convertor is unlocked? The reason I ask is that there are 2 types of TCC solenoids(NO and NC). When I bought my new transmission it came with the wrong solenoid and I had to change it. Not sure if this is the problem you are having or not.

 

It feels like a stumble and bucking sometimes when holding it steady at about 30. I did some checking and I have 12v at 2 of the 3 leads to the trans and a ground does this sound rite?? When I ride the brakes it shifts fine the tach doesn't surge or nothing. But I am only going like 35 so it is probably in 3 or 4 th anyways. Thanks

 

If it was the TCC you'd have a noticeable surge, not a stumble.

 

Not exactly if it is locked up and won't shift out of gear the engine will stumble almost like a bog. A high gear at a low speed in a manual tranny.

 

A bog and a stumble aren't the same thing to me.

 

The most likely cause is that whoever built your trans used a different wire setup. When I was diagnosing my TCC problem I looked in the shop manual and there is about 5 or so different wiring setups and configurations. If you have your old trans wiring setup compare it to the setup currently in the transmission. Use a millimeter to determine if your new transmission has the same switches and electronics for example normally closed or normally open. If everything is the same then your temperature switch is closed or shorted. If the temp switch is closed the 4'th gear switch will act as a ground for the TCC solenoid and it will bog once it shifts into 4'th around 30MPH (If will feel like you are in too high a gear at low speeds in a manual transmission car). The temperature switch locks the TCC when the transmission gets to hot (270 degrees if I remember right) to help cool it down. Some wiring setups don’t even have a temperature switch so if yours setup doesn’t have one ignore what I have said.

You can also find the wiring diagram for the most common wiring setup found in the 700-R4 here: https://www.thirdgen.org/techbb2/sho...hreadid=244424

 

That helped out alot. What I need to know is with the pan off I have 3 switches the wiring goes to and then to the solenoid. Which switches are what??? This trans has one on the drivers side one in the middle and one on the passenger side. Does anyone know or is there a way i can find out?? I will take a pic and try to attach it. THanks!!!

 

this is it

 

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It is very hard to see, do you have "macro mode" on your camera it would make it much easier to view. From the picture I can tell you have a 4'th gear switch and a 3'rd gear switch so both the wiring diagram posted above and the one in my link are not what you need. If you could take a better pic showing all the wiring under there i could help you a lot more.

Do you still have your old transmission? If so just pull the wiring harness and sensors out of that and put it into your new trans.

 

It is hard to get a good pic under there!!! I bought the car in pieces no motor and they said the trans was rebuilt. I am pretty sure the trans is from something in 84 the first number on the trans code is 4. I had to find a tailshaft from another camaro due to the one i had didn't have the bolt holes. So I kind of think it is from an astro or full size truck. Thanks for the replies. I will try to get a better pic tonight.

 

If you don't know what's in there now, you're probably better off getting the switches you need and making a new harness.

 

Take a look at "A" in the second picture. I think that may be the part that needs to be replaced.

http://www.highperformancecars.com/crosley/lockup1.htm

 

jfreeman74,
That link you posed is the most common wiring configuration that thirdgen’s have. maroguy1 has a different wiring setup, he has a 4’th and a 3’rd gear switch.

I will try to scan the wiring diagrams from my shop manual this weekend, that should help out some. The problem is you don’t know how the wiring should be since you don’t know how the original transmission was setup.

If all else fails you can just pull a wiring setup from a junk yard off a same year, model, and engine car and put that in.

 

An 85 should have this wiring:

<img src="http://www3.telus.net/~crussel/tcc_wiring.gif" width=80%>

 

That drawing is great!!! But I have 4 actual switches in the trans. There is one next to the servo on the pass side one in the middle and one on the drivers side in the front. Then there is one next to the solenoid. Which has to be connected to the solenoid. Because one of the wires goes to it and the other goes to the solenoid. Sorry camera took a crap. THanks!!!!!!!! Welcome to the nightmare with this car!!!!!!

 

Oh and the solenoid is green.

 

Is there any way you could sketch out a wiring diagram of the setup as it is now?

 

I don't believe you have a wiring setup that come on any 85 Iroc. From all the diagrams I found no fuel injected 85’s have that switch up by the solenoid. Also Looking at your picture you have a 2 pole 4-3 downshift switch which I believe only pre-85 700R4’s got (may be wrong on that). I think your going to need to go to the junk yard and pull a harness and switches out of a 85 iroc.

 

I am pretty sure the trans is from an 84. The first number in the vin is a 4. The trans code is 4mk215at. I do not know what vehicle though. But it had to be something other than a camaro due to me having to change tailshaft housing. Camaros are hard to come by in the junkyards here. If they do have them they are v6's or tbi cars. I called around for a motor for this thing and all I could find was a tpi 305 for 2000$ So actually finding an 85 iroc tpi with the trans in it is going to be next to impossible. I will try calling around on monday.

 

just post a wanted ad in the thirdgen classifieds and someone will have what you need.

 

allrite Thanks all.