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TCC Lockup Solenoid Stuck On? Code #?

21K views 23 replies 6 participants last post by  rivera405 
#1 ·
I've had an ongoing problem with my trans acting funny for over a year. It comes and goes, and sadly, I've learned to deal with rather than take action to fix it.

Pretty sure I've narrowed it down to the TCC Lockup solenoid always being stuck ON/Locked, or at least that's what it definitely feels like. Always bogged down, shifts into higher gears too soon, very hesitant to unlock and downshift unless going WOT and often lurches violently when coming to a stop, sometimes until it stalls out and dies. I acts like someone driving a manual trans and never using the clutch.

I have a data cable and a laptop now, so I'd like to see if I can come up with any trouble codes in the next day or so. Since I've never used the cable for diagnostic work, are there any suggested programs or particular codes I should be looking for?
I'd rather try this route first before dropping the pan, cutting, splicing and throwing parts at it, just in case it's being caused by something else entirely.

Thanks in advance!

-Brian
 
#2 ·
Scanned with Datamaster several times now and NO DTC's on either the engine or trans.

TCC duty cycle goes from 0% to 99% immediately when I give any throttle, regardless of gear selection, even in 1st and reverse.

Only unlocks reluctantly when coming to a stop (if it doesn't die) after clunking around and lurching, or when going WOT. No TCC stuck on code or anything.

Is this most likely a TCC lockup solenoid problem, or is it possible there's something wrong with my PCM since no codes are being thrown???
 
#3 · (Edited)
Issue still comes and goes, but absolutely ruins driveability when it rears it's head, most notably during/after LONG drives on freeways with the torque converter locked up several hours at a time. Recently drove back up to PA from TX, and it's been acting up 90% of the time whenever I'm on surface streets.

Reverse seems to be the worst! Bogs then lurches hard and fast backwards, chugs and sputters, and wants to conk out real quick unless I throw it into N while still rolling backwards, then into D.

Still no DTC codes.

Kinda planning on just putting a new TCC solenoid in the pan and hoping that takes care of things. Is there just the one TCC solenoid?

IIRC, the solenoid was fairly easy to get at and swap out? Easy access in the pan, 2 bolts, 2 wires to solder, and that's it?

Anybody know the part number off hand?

Already got burned bad by a trans shop out in CA that claimed to have fixed the problem, but never checked the TCC solenoid, so I'm a little hesitant to take it to another shop, unless you guys have any shining recommendations for trans shops in the greater Allentown/Bethlehem/Philadelphia area of PA?

Any input is greatly appreciated!

Thanks!
-Brian
 
#6 ·
The PCM grounds the signal wire to the TCC solenoid to activate it. Otherwise it'll be around 11 or 12V. Look in your manual to see which wire that is, then just shave away a little insulation and connect to the wire, run that wire into the cabin and then monitor the voltage while driving.
 
#7 ·
What manual would you be referring to? I should, but don't, have any FSM's or anything like that at the moment. I had an ATSG 4l60e manual but can't find it for the life of me. I'll try to look up online which wire it is though.

Would I be best off tapping into that wire on the the trans wiring harness right before the plug for the trans, since that would be more likely to detect a ground in the wiring somewhere between the pcm and trans if it was a wiring problem?

Or would that be fairly tricky, and be better off tapping into that wire where it comes out of the pcm just so I can be sure whether there is some kind of sensor or pcm problem commanding lockup when it shouldn't?

My guess is that the closer to the trans I can monitor the signal the better?

Thanks!
 
#8 ·
Found this on LS2.com forum, guessing the trans wiring would be the same for all LT1 cars, whether B of F body?

http://www.ls2.com/boggs/a4/autotransinlineharness.htm

If so, I'm assuming I want to go by the first "Transmission Side" connector, which would be the one that plugs into the trans?
 
#10 ·
Just going off memory, that's right for '94-96 B-bodies. '94s didn't have the U (TCC PWM solenoid) but other than that, yes.

Just my two cents - I'd get a PCM wiring diagram and tap next to the PCM. Then just run the wires into the cabin.
 
#11 · (Edited)
Decided to tap into the Tan/Black TCC wire right before it goes into trans, just in case the wire was grounding somewhere between the pcm and trans connector. Little more work, but better peace of mind I guess.



Ran a wire up into the cabin from the trans harness and hooked it up to an old volt gauge, figuring it'd be way easier to watch that while driving vs. trying to attach multimeter leads in place, watching the little screen, etc.

Hot lead was the end of the lighter socket plug going into the volt gauge, and ground lead was aux added wire coming off TCC wire, also attached to the back of the volt gauge, if that makes sense? Electrical terminology isn't one of my strong points.




Looks like the pcm is commanding the lockup/unlock just like it should!

Always showing exactly 12 volt reading until the car reaches 35+ mph at very light throttle in D or OD, then the reading instantly drops to 0 volts as the pcm commands lockup by grounding the wire, correct?

Also did the TCC unlock brake tap test when lockup was commanded (0 voltage reading) while light throttle cruising above 35 mph. Quick tap on the brakes instantly popped the voltage from 0 back to 12, which would mean the pcm seems to be commanding the TCC lock/unlock just as it should.

Unfortunately, the the physical converter locking/unlocking did not seem to match what was going on with the gauge whatsoever.

This leads me to believe that my problem most likely is a malfunctioning TCC solenoid, or, faulty TCC wiring inside the trans between the connector, although much less likely I'd imagine?


Make sense? Anything I'm overlooking or other things to consider before I got ahead and order a new TCC solenoid and drop the pan to pop it in?

Any chance the TCC PWM solenoid would have anything to do with this? Datamaster scans show an instant jump from 0% to 99% TCC duty cycle, as soon as a gear is selected, regardless of PRNDL selection, but still no DTCs.
 
#12 ·
Went ahead and ordered TCC Lockup solenoid a few weeks ago, planning on installing in the next few days after a trans fluid flush and filter change.

When I have the pan off, is their anything else I should look for or poke around at?

At least one person has mentioned that if the TCC solenoid isn't the problem, then I might have some problems in the valve body, at which point things might be a little more serious?

Any tips or insight is appreciated!

Thanks!
 
#13 ·
have you checked and ruled out your brake switch?
 
#16 ·
Monitoring the TCC Lockup circuit, a quick tap on the brakes un-grounds the 12v circuit, sending the "unlock" signal to the trans, which I wrote about in an earlier post in this thread.


"Always showing exactly 12 volt reading until the car reaches 35+ mph at very light throttle in D or OD, then the reading instantly drops to 0 volts as the pcm commands lockup by grounding the wire, correct?

Also did the TCC unlock brake tap test when lockup was commanded (0 voltage reading) while light throttle cruising above 35 mph. Quick tap on the brakes instantly popped the voltage from 0 back to 12, which would mean the pcm seems to be commanding the TCC lock/unlock just as it should."


This says to me that the brake switch would be working correctly. Could I be overlooking anything there?
 
#17 ·
This is where things get a little murky for me. "Fine" is hard for me to define in this scenario.

Trans seems to shift a little harder than normal, and earlier than normal, and the motor seems to lug a bunch at 30mph +, unless you tip into the throttle fairly hard. I attributed that feeling to the converter always being locked up, making shifts feel harder, and the feeling of upshifting into too high of a gear too soon.

Does that make sense?
 
#19 ·
Reason why is that the TC is not eating up the shifts anymore, it is solid.
usually when a car shifts, the TC will eat the shift up, plus not lock.
If locked, which yours is, the car shifts to the next gear at looks to be 30, it will lug.
Now if you didnt fix the lock up problem and raised that shift point it would no longer lug.
 
#20 ·
Finally works right!!!

Success! Swapped out the TCC solenoid and installed new filter tonight after flushing with several fresh quarts. Seemed to finally behave normally on the initial test drive on a little loop around town and merging onto the freeway. It's been a long time!

Really not sure how this was looked over as a possible culprit last time I took it into a trans shop for diagnosis, and was charged $300 with no real change in behavior, but I digress.

I did notice that the fluid I flushed out was really quite dirty, and the magnet in the pan was pretty darn goopy with a slightly metallic dark charcoal color.

I would imagine that driving around for a year with the TCC generally stuck on would wear the clutches in the converter a bit and leave a bunch of clutch material floating around in the fluid?

How likely is it that the clutches in there can physically wear out under these circumstances?

I also noticed the TCC solenoid I pulled out was "Rostra" "Made in USA", which was the same thing I ordered and installed. Was that brand ever OEM? If not, then I assume when Dana@Probuilt built the trans, he put a fresh one in, and apparently that only lasted a very very short while before malfunctioning?

There also happened to be either a very small ball bearing, or more likely a steel checkball that fell out of the trans at some point during the solenoid R&R. I assume this could have been making things act wacky in there if it were just floating around, or stuck in some orifice.
Not sure if the trans shop that attempted to diagnose and fix my issue by replacing my Torlon checkballs with steel, without any mention or consent, might have accidentally dropped a checkball and lost it in the trans during the process....... Makes me wonder.

One last quick question. Approximately how much fluid do I need to add after completely draining the pan? 4-6 quarts? I ask because I have a really tough time reading the revised trans dipstick without holes. I added 4, then kept checking, and assumming I'm reading it correctly, finalized the fill at about 5.5, maybe 6 quarts. That sound about right? Any tips on checking the dipstick, other than car level, in park, with engine running?


Thanks again for all your tips and pointers! Very excited that this may have finally fixed my trans so that the car is actually fun to drive again!
 
#22 ·
With that much clutch dust floating around, I'd recommend you flush the fluid in another 500-1000 miles. Don't bother dropping the pan, just pump the fluid out using the cooler line method. I just did it last night on one of my cars, took 20 minutes start to finish and I didn't even have to jack the car up.

If it keeps on running, don't worry about it.

As far as the checkball - yeah, could be just an extra. How big is it - 0.250" diameter?
 
#23 ·
Yeah, kinda thought that might be a good idea after reading some other threads. I've used your write up a few times now, including pre-solenoid install, definitely works well!

I was thinking today that the clutch dust is also likely to be dust from the other clutches, and not just the TC clutches, since the converter always being locked up will put a lot of extra strain on the clutches any time it shifts, or when the car is straining up a hill with the TCC locked up.

Definitely wish I would have gotten around to doing this a lot sooner, that's for sure. I just hope there wasn't too much damage done. Hindsight is always 20/20 though, right?

On the checkball, it was definitely a small one, my guess would have been around 1/8" . Possible it was on the driveway from something else entirely and just didn't see it beforehand. Ended up losing it in the shuffle under the car before I could measure or anything.
 
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