4L80E TCC Slippage Problem

Attachment 86582Attachment 86583 Here is my log and current tune.

Hi guys,
In my ls swapped blazer I have a 6.2 Ls3/4l80e combo. It is ran with the e38 and t42. It has a Circle D Specialties 3200 stall/TSP cam. My current issue is when I am driving down the road with the gear selector in overdrive, it will throw a P0894 code for internal component slippage and go into full line pressure when the following conditions are met: trans is in 4th gear, and tcc is locked. However, when you have the gear selector pulled down into 3rd, the transmission shifts fine, and will go into lockup while in 3rd gear and no code is set.

Firstly, I tried to resolve the problem myself by changing the tcc lock up to a later time, thinking this would keep it from slipping. This did not solve the issue.

Now, I got to looking at the tcc slippage. As you can see in the log, while in 4th/lock up, the slippage is ~130. Is that too much? Is there something that can be changed in the tune to resolve the amount of slippage? Or, is my brand new converter shot? In the attached log, I was manually locking up the converter to keep it from jumping out of gear and setting the code like described above.

I am new at the whole tuning side of things and just trying to see if I could fix this myself.

Any help is appreciated,
Clint

your trans needs tuned for that converter, mine was acting up until I tuned it.

you need to log TCC duty cycle. If it's tuned and 99% and slipping over 3rpm you need a new converter, the o-ring on input shaft is cut, transmission pump/tcc valves worn

Quote:

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Originally Posted by staytuned

you need to log TCC duty cycle. If it's tuned and 99% and slipping over 3rpm you need a new converter, the o-ring on input shaft is cut, transmission pump/tcc valves worn

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Do I just add another channel for duty cycle? And also, should I log with the trans in 4th gear and locked? Should I change the duty cycle before I do this? I?m not sure where to look to see what it is currently set at.

So I just went for a ride to see if changing the minimum duty cycle to 80% would make a difference in keeping the tcc locked in. In this log Attachment 86610 you can see that between the time 2:20 and 3:10, that the tcc randomly unlocks. Also, I added the duty cycle channel so that I could read that. While it is engaged it reads 99-100%. So this makes me think it is not converter related. At least not right now. Could a bad tcc solenoid cause it to not hold lock-up? The tcc solenoid, pressure control solenoid, and pressure manifold switch have not been replaced. Only the A and B solenoids have. Any ideas?

Clint

At 3:02.38 in to your log the DC is 80% ramped to 90% and the slip is over 700rpm pulling down to 200rpm slip in 1 second then slowly to 150 but never below. So everything is working correctly except the converter clutch. I doubt it is a solenoid problem because it is working. You can try 98% ramped to 99% Usually when we see this it is a bad converter. Or the converter wasn't built correctly. You can tune it to apply with less throttle and torque but it still should hold at that TPS and air flow rate.