tcc issue

[timdesu2000]

Hey all. Im having an issue with my tcc locking up in 2nd 3rd and 4th gear after the transmission is hot. Worse the hotter it is outside. Trans was recently freshened up and a new tcc solenoid was installed at the same time. Had the same problem before then trans was freshened up. I havent checked to see if Im getting a signal out of one of the switches yet to see if its fooling the ecm but it has a turbo tweak chip thats supposed to keep lock up off untill after 45 mph. It acts just like a sticking solenoid not bleeding off the tcc suppply fluid but with the same issue with two solenoids Im thinking its something else. Just wanted to see if anyone else has run across this?
Thanks,
Tim

 

[SSedan64]

Try unplugging the Trans TCC connector & see if it stops.
It's very possible to get a bad new TCC Solenoid.
TCC Apply Valve in Pump could also be leaking or stuck.
http://www.sonnax.com/system/announcement/77805-K.pdf
http://www.sonnax.com/product-lines/transmission/parts/1803

 

[mikestertwo]

It's most likely a bad TCC solenoid...pretty common.

 

[timdesu2000]

I will try to get it unplugged after its hot and doing what it does. Its just perplexing that it does the exact same thing with a new solenoid. It could be a leaking valve in the pump. New bushings were installed in the pump but the valves were not removed. Under light throttle when it does this the tcc will lock and unlock repeatedly. If you apply more throttle it will stay locked in even in manual second.

 

[timdesu2000]

I drove the car to work today and this afternoon with the hot temps it acted up. Did determine that the tcc will release when you push the brake pedal and take power away from the tcc solenoid. Looks like Im dealing with an electrical issue. At this time Im thinking the driver in the computer is wigging out in the heat. As I drove the car with the ac on it actually got some better and didnt lock in untill higher speeds but still not correct. When it acts up it will go in and out as soon as you get in to second gear and then stay in from there on. If anyone else has run across an ecm doing this I would like to know. Thanks,
Tim

 

[standupjskiguy]

The reason they fail is because it is a coil of wire wound around a plastic spool. The wire
is stretched as it is wound creating pressure on the plastic spool. Inside that spool is the
metal rod that holds a ball to close the passage for the TCC to drain. While the solendoid is energized,
the rod is held up against the ball. When it is not energized, it is suppose to release the ball.
As heat softens the plastic, the spool collapses little by little until it keeps the rod from sliding freely
inside the spool. It holds the ball, which wont release fluid and the TCC sticks. Once the car cools down,
the plastic thickness of the wall decreases and releases the rod and it works until the car warms up again.
What I did on all of mine was to take the solenoid apart and drill out the plastic inside the hole
with the next largest drill bit. It's a little tricky because you have to break some spot welds
to get it apart, but you don't have to reweld it to get it back in.
It could be that it was replaced with NOS and it was bad because it was old.
Hence it is possible for you have have a defective new one.
The TCC in the wife's 85 went bad at 80,000 miles and many years of service.
Shortly after the TCC in my 12,000 mile GN went bad so over time the plastic can begin to collapse.
If you disconnect it when it is cool so it never engages. Disconnecting after it's hot won't tell you anything because
it's stuck and won't loosen until after it cools down.

 

[timdesu2000]

Thanks for the info and I fully agree with that. My issue is that the ecm seems to be commanding tcc at low speeds and starting in second gear. Seems to be worse with inside temps of the car and not trans temps. When the tcc engages at low speeds or when it shouldnt I can apply the brake pedal and it will release. This tells me its an electrical issue and not a mechanical binding of the bleed off check ball. Im leaning towards a defective driver in the ecm at the moment

 

[standupjskiguy]

When my TCC went bad it also caused early upshifting. The ECM only controls only the TCC lockup and not the shifting on these cars.
So starting in second gear is not caused by the ECM. I never had that but I had early upshifts.
The shifting is controlled by the TV cable position and the governor. I believe the reduced flow through the TCC causes
increased pressure through the governor and that was the cause of early upshifts with a bad TCC. So even though
the TCC may not be locked, flow is still reduced enough to have an effect.
I still think disconnecting the TCC when the trans is cold and driving the car to see if all your problems go away is worth a try.
Either that or a spare ECM. I just got one off Ebay for an 86-87 for about $50.

 

[timdesu2000]

I guess I need to clarify. The transmission shifts properly but the tcc will start applying in
Second gear when the temperature is hot. If I apply the brake which removes power to the tcc solenoid the torque convetor will release.I hope that helps. I'm looking to get a new delco ecm. Can get a good price on it. I'm hoping this will help with a hard start when outside temps are hot also. Will keep you updated. Thanks for all the input.

 

[timdesu2000]

Did some more testing and found that when its hot outside that the speed sensor readings are way off. I was was doing 20ish and it was showing 50 or more. Thats why the computer is commanding lock up. Havent pinpointed the issue yet but maybe the digital ratio adapter.
Will keep you updated.

 

[timdesu2000]

I seem to have the issue fixed. Its crazy but seems the upper speedo cable was a bit too long. When it gets hot it expanded and was binding in the housing causing the speed sensor to be way fast. I am not sure if it was like a coil unwiding or what that caused the high speed sensor readings but after shortening the cable and a 25 mile drive in the heat today it worked perfect. Lock up right at 45 mph. Hope this may help someone in the future.
Tim