I have tuned the crap out of my trans in the past few weeks.
I'm trying to get my converter to hold at lock-up.
I have lowered the forcing table to the point that 1 -> 2 shift pressure tables are set at -96 in the lower ft. regions.
Min duty cycle is 99 the max at 100.

Now for the problem.

Sometimes the ecm will have a bad day.
it commands the tcc to lock and I can feel it lock very very soft, but it will slip 1000+ rpm. This happens EVERY time the tcc locks during a trip. Not at times like later on in this post.
One day the tcc will lock, but won't "hold" for the whole trip to work. Then, the next day it will work correctly.
This happened to me Friday on the way to work. And on the way home it did it again. It would always lock but still slip. After a bit of a temper tantrum and trying to blow the truck up with a few WOT throttle runs, the tcc starts locking hard and holding like it has in weeks past. And is still working fine now.


Also some times the tcc will lock-but slip up to 1000 rpms while driving. if I release the throttle then resume, the TCC will disengage then re-lock and hold like it should.
Is there some un-known table for the tcc apply clutch operation?
Or is the TCC solenoid or other "hard part" about to take a crap?

I will post a scan and bin in a bit.

 

I'm thinking I should have posted this in the drive train section, so maybe some of the trans builders could help out.
Anyone every heard of a TCC solenoid failing in the trans?
I would "think" it would just fail, but it works more than it doesn't. It also does not seam to be affected by trans temp.

 

I have never read of a TCC solenoid failing. I am with you on your thought that solenoid fails totally, not a good today bad tomorrow. I have not seen anything in my tuning software to tune TCC alone pressures. I would like to soften the TCC apply with my PI (It locks HARD). My first thoughts were heat and viscosity of the fluid but you are saying does it cold/hot. I wouldn't rule out the clutch in the TC. When talking to PI during my shopping I guess the clutch in thiers was the deciding factor. They were quick to sell how difficult it was to come up with a clutch and materials that would hold and last with the heavy trucks.

 

To help figure out if its hardware or software errors. Go for a quick trip, and use the VCM controls, set the PWM Solenoid at 100% and enable the TCC Solenoid. If it still slips well then it might be the torque converter itself.

 

Can you not do this in your Min TCC %Duty Cycle vs Line Pressure vs Transmission Temp.?

Wilde, my guess is the torque converter as well.

 

I've tried this while the converter is slipping. but that just mean the ECM is telling the torque converter to lock. But I guess that right there rules out the programing.
The only reason I keep coming back to the tune is because if tcc is sliping and I reprogram it, it will start locking again. But myabe I've just been luck seams how it comes and goes so much.

Trans up to temp.
My dad and I was comming home the other day from the lake with the boat. I was telling my dad about the problem. We were about 2 miles from the house, I let off the throttle to show him how it feel when the tcc locks and holds, and the POS didn't lock. (this is the first time it did it while towing). Plus we had drove about 60 miles with the tcc locking and holding.

Two days before that, trans cold.
I get in my truck in the morning to go to work. the tcc would not lock and hold.

 

Transgo makes a kit upgrade for the TCC slip problem, its a combination shift kit and upgrade. You pull the valve body out and put different springs and plungers in. Fairly simple. The 4L60 has the same problem and causes premature burn up. Sometimes the solenoids can act up and usally its the ECM, to test this you need to get your hands on a shaffer shifter so you can manually controll your shifts to check if its the ECM of faulty solenoids. Hope that some of this info helps...

 

it could be the noid they do do this at times i have seen it a ferw times i would if i were you change the wireing harness and the noid

 

TC lockup solenoid is toast in my 60e right now, it happens. If it was me I would get the solenoid replace and order a restall or get a new tc like you were wanting to anyway.

 

You are a swap truck. It's not far from beleiveable that certain things that normally don't go bad (TCC noid) on others wouldn't go bad on yours. Just reasoning with ya, I hear your frustration man. Working sometimes and not others sounds like electrical connection (noid or harness).