6L80 TCC tuning help

[DickForster]

2018 Silverado 5.3L, rebuilt 6L80 with new Precision HD (billet case) torque converter. I have watched lots of youtube videos and reading and went with this approach - no TCC in 1 through 3, 0 slip TCC in 4 through 6. Increase the lock pressure. Also used bearcat to make shift rpm adjustments, but I don't think that speaks to the TCC performance that I am seeing.

Regulator offset is set to 90 psi, gain 1.0. All slips are set to 0. Apply Ramp table set to 300 above 0 slip error, Max Pressure 200 psi.

In the scan, when the truck first shifts to gear 6, a few seconds later the TCC locks, the desired slip goes to 4.5 rpm??? That is nowhere in the tune that I can see, should be 0.
The line pressure there is around 45 psi. Where is the 90 psi offset?
Anyway, the speed is varying a bit as I am in traffic. When the line pressure goes to 600 psi, that's where I used the Scanner override to force TCC Lock. TCC slip goes down but is not a hard 0, small wiggles. Then I enable cruise at 65mph. Then I set TCC Lock to Off and the line pressure goes to 0. Then I disable the TCC Off and the line pressure goes to a stable 110 psi, yay, but eventually it drifts downwards to 70 psi or so. This doesn't seem to match how I would predict it to behave from the tune.

Could use some expert advice here. Thanks.

[TransGo Robert]

2018 Silverado 5.3L, rebuilt 6L80 with new Precision HD (billet case) torque converter. I have watched lots of youtube videos and reading and went with this approach - no TCC in 1 through 3, 0 slip TCC in 4 through 6. Increase the lock pressure. Also used bearcat to make shift rpm adjustments, but I don't think that speaks to the TCC performance that I am seeing.

Regulator offset is set to 90 psi, gain 1.0. All slips are set to 0. Apply Ramp table set to 300 above 0 slip error, Max Pressure 200 psi.

In the scan, when the truck first shifts to gear 6, a few seconds later the TCC locks, the desired slip goes to 4.5 rpm??? That is nowhere in the tune that I can see, should be 0.
The line pressure there is around 45 psi. Where is the 90 psi offset?
Anyway, the speed is varying a bit as I am in traffic. When the line pressure goes to 600 psi, that's where I used the Scanner override to force TCC Lock. TCC slip goes down but is not a hard 0, small wiggles. Then I enable cruise at 65mph. Then I set TCC Lock to Off and the line pressure goes to 0. Then I disable the TCC Off and the line pressure goes to a stable 110 psi, yay, but eventually it drifts downwards to 70 psi or so. This doesn't seem to match how I would predict it to behave from the tune.

Could use some expert advice here. Thanks.

You did not record enough transmsision related parameters to really be able to analyse how everything but you lock-up is locking up solid, the little fluctuations you see are not actual slip that's just the sensors that are not that precise. For what it is worth, I would not go higher then 75-80 psi on the TCC solenoid output pressure, higher then that is not needed to keep the clutch lock and very hard on the flimsy stamp steel lock-up piston used in those converters. PSI the pressures you logged are TCC solenoid output pressure, nothing to do with line pressure.

[DickForster]

I will take another scan tomorrow with all transmission parameters, not just the TCC ones. Thanks.

[TransGo Robert]

I will take another scan tomorrow with all transmission parameters, not just the TCC ones. Thanks.

Sounds good, here's a channel configuration file you can use to make sure we get all the PIDs we need. 6L80.Channels.xml

[DickForster]

I already took this new scan just now before seeing your post. If it is not enough, I will do another scan later today. Thanks! Of note - this time I see TCC slip is commanded to 0, not 4.5, so that has resolved itself somehow. Did not change the tune. Apart from my not understanding the TCC line pressure settings, it is shifting ok but does have a bump downshift 2-1 when cold. Full disclosure - last week I got a P0011 code so the VVT has an issue. Runs ok but idle is very slightly lumpy. Hopefully it is just the solenoid or valve but have not investigated yet. Also, DOD is disabled, that's the only engine tune mod. As before, I did use the scanner to force TCC On and Off for about 10 seconds each.

vcm-scanner-2.jpg

[TransGo Robert]

I already took this new scan just now before seeing your post. If it is not enough, I will do another scan later today. Thanks! Of note - this time I see TCC slip is commanded to 0, not 4.5, so that has resolved itself somehow. Did not change the tune. Apart from my not understanding the TCC line pressure settings, it is shifting ok but does have a bump downshift 2-1 when cold. Full disclosure - last week I got a P0011 code so the VVT has an issue. Runs ok but idle is very slightly lumpy. Hopefully it is just the solenoid or valve but have not investigated yet. Also, DOD is disabled, that's the only engine tune mod. As before, I did use the scanner to force TCC On and Off for about 10 seconds each.

vcm-scanner-2.jpg

Sorry for taking so long to reply, I had to travel for work. You lock-up is working fine aside from the fact that it is not commanding it in 6th gear unless you are above what looks like 42 mph but you probably did that on purpose. As for the clunk downshift I would need to see more PIDs, throttle and fuel trims for sure, this unit is super piecking when it comes to engine side of things not being 100% perfect causing downshift clunks. That P0011 unless it was jus because you were just low on engine oil, definitely will need to be addressed before worrying about any kind of downshift clunks. If you can take another log with the PIDs in my channel config it will be easier to assess what is causing it.

[DickForster]

Thanks Robert, i will make another scan with more PID's.

Hmmm, this is a headscratcher for me. Started the truck today, check engine light is off so the P0011 went away. Nice. By the way, the engine oil is fresh dexos approved 0W20 synthetic and at correct level. After about 15 minutes driving, noticed the trans is at 160 degrees. Hotter than normal, as this trans has the STL010 fitted. The TCC was not locked. No matter what I did, and I was just cruising in 6th gear at 65mph, the TCC would not lock. Didn't have the VCM Scanner set up so could not check anything. Ghosts in the machine. It seems to be possessed.

[TransGo Robert]

Thanks Robert, i will make another scan with more PID's.

Hmmm, this is a headscratcher for me. Started the truck today, check engine light is off so the P0011 went away. Nice. By the way, the engine oil is fresh dexos approved 0W20 synthetic and at correct level. After about 15 minutes driving, noticed the trans is at 160 degrees. Hotter than normal, as this trans has the STL010 fitted. The TCC was not locked. No matter what I did, and I was just cruising in 6th gear at 65mph, the TCC would not lock. Didn't have the VCM Scanner set up so could not check anything. Ghosts in the machine. It seems to be possessed.

Most GM and also other make will cancel lock-up when it detects a knock sensor issue, a lean condition, misfires, or a cam actuator issues. It probably tripped a code or has pending code causing it to not command lock-up to help save the engine and the catalytic converters. The transmission in turn will run warmer since an unlocked converter is the main source of heat for the transmission.

[MAF-tuning]

https://www.youtube.com/watch?v=KhPB7-RWQbY&t=12s
GM 6L80 Transmission Tuning Tips | HP Tuners

[DickForster]

Finally got to take another scan with the requested parameters. No fault codes except for a dead TPMS sensor. DOD has been disabled. This drive, the transmission was not engaging TCC in anything but 6th and even then it seemed reluctant. Long gentle cruise in 5th, no TCC. Ugh. In the attached image, I intentionally used cruise control and tapped to add 1 mph every second or so. Every increment, the TCC slips. Ugh. The TCC Offset pressure is sort of described as a minimum value, but it doesn't work that way in this tune for sure. Need to understand what it actually does. It may be time to delete this tune and start fresh. It just seems to behave differently on different drives. In the meantime, I'll watch the youtube video linked but it may be one I've already watched.

scanner_04012024.jpg

https://www.dropbox.com/scl/fi/8nfqg...icc7emjor&dl=0
^^^ was unable to attach the scan, so linked it here.

[blindsquirrel]

To trim down a too-long log file to exclude the not relevant parts, zoom in/out so that the relevant bits are in the window, then...

screenshot.01-04-2024 08.59.21.png

You can clip out multiple sections from a single log.

[DickForster]

To trim down a too-long log file to exclude the not relevant parts, zoom in/out so that the relevant bits are in the window, then...

screenshot.01-04-2024 08.59.21.png

You can clip out multiple sections from a single log.

Thanks!

1. Scan log where 1mph cruise increments occurs and TCC slips.
2. Scan log where 5th does not lock TCC.

[TransGo Robert]

Thanks!

1. Scan log where 1mph cruise increments occurs and TCC slips.
2. Scan log where 5th does not lock TCC.

The momentary ~50 RPM TCC slip when you accelerate using the cruise control is ok and desirable in my opinion. But the no TCC command when not in 6th is not. It is not an engine sensor issue like I thought, all looks well in there, it must be something not setup right in the tune. That's the dark part for me, I am not very good at it. Hopefully someone else can look at your tune and tell you want to change to get it to work again in 4th and 5th. I will look at it myself and get back to you if I see the problem, but don't expect much, I am very green at that side of the equation.

[TransGo Robert]

I will look at it myself and get back to you if I see the problem, but don't expect much, I am very green at that side of the equation.

Well I was wrong, I think I see the problem. it seems obvious to me unless I am not understanding how those tables work. You have the settings for 4th 5th adn 6th to not lock-up under 25 or so throttle % opening too high miles per hours wise. 5th apply for example is at 49 mph at 25% throttle, so that's why it is not locking up in 5th. Look at the screenshot I took, your TPS is at 22.7%, you are in 5th gear and the road speed is 42.87 maph but you have your tune set to not lock up until 43 mph at 19% throttle and 49 mph. I think if you simply lower those apply and release tables to get it to lock at lower road speed, it will lock in 4th 5th and 6th like it should.
No TCC.png

[DickForster]

Well I was wrong, I think I see the problem. it seems obvious to me unless I am not understanding how those tables work. You have the settings for 4th 5th adn 6th to not lock-up under 25 or so throttle % opening too high miles per hours wise. 5th apply for example is at 49 mph at 25% throttle, so that's why it is not locking up in 5th. Look at the screenshot I took, your TPS is at 22.7%, you are in 5th gear and the road speed is 42.87 maph but you have your tune set to not lock up until 43 mph at 19% throttle and 49 mph. I think if you simply lower those apply and release tables to get it to lock at lower road speed, it will lock in 4th 5th and 6th like it should.
No TCC.png

Thank you, that was from the BlueCat tune. I will make that change to 5th/6th TCC and expect it will be good. I will then do another scan. It's getting close to a working tune then, that's great.

[DickForster]

Changed the 5th, 6th gear TCC rpm, disabled TCC in 4th, and looking much better, thanks everyone.

scanner_04012024-new-tune.jpg

[TransGo Robert]

Changed the 5th, 6th gear TCC rpm, disabled TCC in 4th, and looking much better, thanks everyone.

scanner_04012024-new-tune.jpg

Yup, that looks very good.