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Torque converter NOT locking up by sjdannen
Started on: 04-22-2013 04:11 PM
Replies: 8 (319 views)
Last post by: MetalBlue85GT on 03-08-2014 10:41 AM
sjdannen
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Report this Post04-22-2013 04:11 PM Click Here to See the Profile for sjdannenClick Here to Email sjdannenSend a Private Message to sjdannenEdit/Delete MessageReply w/QuoteDirect Link to This Post
In searching, I find that most problems with the torque converter is that the solenoid has gone bad and the torque converter is staying locked up when coming to a stop. I have kind of the opposite problem, the torque converter doesn't lock up. If I am still accelerating lightly when it shifts in to third gear, the car jerks and hiccups. If I jam the gas pedal, I'm guessing, that either the detent cable or the ECU has told the tranny not to engage the torque converter. If I let off the gas to that is isn't accelerating, the jerking stops but the TC still isn't locked up. If I disconnect the connector for the TCC, as expected, no hiccups what-so-ever.

I have replaced the transmission filter and gasket as well as replaced the TCC solenoid. When replacing the filter, I believe that it took 3 quarts and is still just a tad low, as if it needs a little more than a pint but that is all. I am planning on picking up another quart just in case being only that low could be sucking air.

I have not done a full flush of the tranny fluid.
Nor have I done a bypass so that the connector that would go to the ECU is on a switch and the line coming from the brake pedal is replaced with a 12V line from the battery. I think the switch is my next step but seeing as how that won't be until sometime later this week, I figured I would ask for any other ideas.

Thanks in advance!
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donuteater306
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Report this Post04-22-2013 04:29 PM Click Here to See the Profile for donuteater306Click Here to Email donuteater306Send a Private Message to donuteater306Edit/Delete MessageReply w/QuoteDirect Link to This Post
Taking into consideration everything you've already done/checked and assuming that you bring the fluid up to the correct level...The only time i've heard of a GM trans. TC not locking-up has been when the thermostat was stuck open and the engine stayed below normal operating temp. The computer wouldnt allow TC engagment. Simple to check.
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TK
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Report this Post04-22-2013 04:48 PM Click Here to See the Profile for TKSend a Private Message to TKEdit/Delete MessageReply w/QuoteDirect Link to This Post
There is a brake switch in line with the TCC. Make sure it's closed.
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sjdannen
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Report this Post04-22-2013 05:04 PM Click Here to See the Profile for sjdannenClick Here to Email sjdannenSend a Private Message to sjdannenEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by TK:

There is a brake switch in line with the TCC. Make sure it's closed.


Thanks, when I had the TCC connector unplugged before I ran a wire in to the passenger area connected to a multimeter, and had my twelve year old watch and report voltage changes. So I am able to confirm that 12V is going to the connector when I am not pressing the brake pedal. Sorry, forgot to mention that.
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sjdannen
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Report this Post04-22-2013 05:07 PM Click Here to See the Profile for sjdannenClick Here to Email sjdannenSend a Private Message to sjdannenEdit/Delete MessageReply w/QuoteDirect Link to This Post

sjdannen

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Member since Dec 2012
 
quote
Originally posted by donuteater306:

Taking into consideration everything you've already done/checked and assuming that you bring the fluid up to the correct level...The only time i've heard of a GM trans. TC not locking-up has been when the thermostat was stuck open and the engine stayed below normal operating temp. The computer wouldnt allow TC engagment. Simple to check.


Interesting, I didn't even know that it took that in to consideration. I can't remember whether engine temp is something that can be monitored through the ALDL port, but I could also verify the temp sensor. Earlier in the year I did notice that it took quite a while for the car to warm up. However, I would think that would cause the torque converter to not even try to lock up, what I seem to be experiencing is that it is trying to lock up but isn't able to so the car kind of stumbles.
Thanks!
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TK
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Report this Post04-22-2013 06:10 PM Click Here to See the Profile for TKSend a Private Message to TKEdit/Delete MessageReply w/QuoteDirect Link to This Post
It's certainly possible the TCC shaft itself is internally hung up. If 12V is being applied to the solenoid, there isn't much else needed. Assuming the passage itself isn't blocked, the converter could be bad.

I'd have to look but I think TCC lock is enabled around 148F. I would expect the engine to at least get that high even without a stat. Now the CTS might be bad telling the engine it's colder than it really is.

A scanner is in order.
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donuteater306
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Report this Post04-22-2013 06:16 PM Click Here to See the Profile for donuteater306Click Here to Email donuteater306Send a Private Message to donuteater306Edit/Delete MessageReply w/QuoteDirect Link to This Post
Sorry, I just re-read your original post. You're right, it wouldn't even try to lock-up.

Strange that when you unplug the solenoid, the problem goes away. What about hooking a test light to the solenoid harness and then going for a drive. Light flickering on and off would confirm the signal from the ecm to rapidly lock/unlock. Obviously you'd need to run a long wire to the interior so that you could watch the light. But this would confirm the signal from the ecm. Then you can work backwards from there.
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sjdannen
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Report this Post04-23-2013 01:50 PM Click Here to See the Profile for sjdannenClick Here to Email sjdannenSend a Private Message to sjdannenEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by donuteater306:

Sorry, I just re-read your original post. You're right, it wouldn't even try to lock-up.

Strange that when you unplug the solenoid, the problem goes away. What about hooking a test light to the solenoid harness and then going for a drive. Light flickering on and off would confirm the signal from the ecm to rapidly lock/unlock. Obviously you'd need to run a long wire to the interior so that you could watch the light. But this would confirm the signal from the ecm. Then you can work backwards from there.


Are you suggesting that both positive and negative side of the test light go to the connector, or possibly put it in series? Oooh, I like the 'in series' idea but it would have to be a low draw lamp because I understand that if there is too much draw there may be a possibility of damage ECU because that controls the final ground.
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MetalBlue85GT
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Report this Post03-08-2014 10:41 AM Click Here to See the Profile for MetalBlue85GTClick Here to Email MetalBlue85GTSend a Private Message to MetalBlue85GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
So this post kind of ends - what ever fixed your issue? I am experiencing the same symptoms.

I will reference your post and start my own. I am going back in for another TCC Solenoid R&R and trying to locate a 3rd gear switch too.
- R&R TCC for the locking issue and that fixed the locking issue. Then after I installed the new TCC Sole I get a chugging of the car when I am above 35mph; cruise on flat ground. Once I accelerate or tap the brake or remove the TCC wires the chugging stops. So I know it has something to do with TCC.

So far:

Fluid exchange and filter replacement have not helped.

I bought my TCC Sole from Advanced Auto maybe you have something in common with that?

[This message has been edited by MetalBlue85GT (edited 03-08-2014).]

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