6L80 TCC Slip fluctuations

[16_Silverado]

I am getting a vibration that I believe is a faint TCC shudder. I disabled TCC in normal so I could drive to work and I am pretty sure I am feeling a difference but it can be hard to tell on some of these roads. So I decided to log TCC slip on my way to work today. I had left the TCC active in tow/haul so it is in tow/haul in the log. I seems to me the trans is struggling to control the TCC Slip with all the fluctuations and spikes after going into V4 mode. However, I have not been able to find an example of what TCC slip should look like. Does this look like an issue?

Stock 2016 Silverado 5.3 & 6L80

Thanks

[RDF1]

post your tune

[blindsquirrel]

https://www.rockauto.com/en/moreinfo.php?pk=9456964 (only kinda joking, I'm generally opposed to any kind of magic additive but have seen this work where the only complaint is TCC shudder and the only other option remaining is a rebuild - I have no info on what horrible problems it might cause long-term)

edit: and assuming the fluid has been changed since the problem appeared, and that it's got the right amount of the right fluid. If not, step #1 is change the fluid. Duh.

[5FDP]

I can't view his log because of my older version of HPT but he could try to raise the regulator gain and regulator offset settings some to try and help with the shudder. As well as reduce the TCC desired slip values.

[hjtrbo]

Slip looks fine to me. Now if there is any clutch material left is another matter. Do what blindsquirrel said. And drop the pan and have a look.

5DFP I think the OP might make it worse if he does that as he still has DOD enabled...

[16_Silverado]

post your tune

The only thing I've done to the tune is disable TCC but I left I active in Tow/Haul.

I know I could make some adjustments to the tune but this is a daily driver with 98500 miles my thought is if I can replace the torque converter at a time it is convenient for me before it fails that would be preferable to masking the problem for a while and having it unexpectedly fail. So I am looking to verify my issue.

Thanks for the replies.

[Estep40511]

I would disable DOD along with lockup until 4th gear on a stock trans and engine. Doing just those two things makes a world of difference....and your transmission will thank you. When the ECM commands AFM to be active, it pulse width modulates the TCC...basically locks and unlocks a few times back to back. and being a tech at GM, I can tell you and show you what doing that to a torque converter does to the converter and trans fluid pump. Id for sure disable DOD if youre going to make any adjustments to the trans at all.

[alabastarbastard]

you need to add more pressure to the tcc clutch and set the tcc gain to 1.

there is a detailed video i think i posted a few weeks back on here regarding the shudder fix, guy made a good walk thru vid on YT on doing it

[Estep40511]

Once you have vibrations, damage to the pump and housing have already occured. At GM, under warranty we get told to only replace converter. But, if you take one apart that just started shuddering, you can see score marks on the pump and housing, thus changing pressure capabilities etc. I rebuilt mine when I built my engine, almost two years and 50K ago. I tuned it to only lock in 5th and 6th gears and made minor adjustments to line pressure and holding pressure. stock rebuild with all GM parts, even the converter(for now). and did the thermostat bypass on the lines going to cooler. Ive yet to have a single issue, knock on wood lol. If you keep the converter from locking, even partially like GM tries to do to make the AFM transition less noticeable, then you will have a trans that lasts for years.

[5 Star Custom Solutions]

I am getting a vibration that I believe is a faint TCC shudder. I disabled TCC in normal so I could drive to work and I am pretty sure I am feeling a difference but it can be hard to tell on some of these roads. So I decided to log TCC slip on my way to work today. I had left the TCC active in tow/haul so it is in tow/haul in the log. I seems to me the trans is struggling to control the TCC Slip with all the fluctuations and spikes after going into V4 mode. However, I have not been able to find an example of what TCC slip should look like. Does this look like an issue?

Stock 2016 Silverado 5.3 & 6L80

Thanks

Been dealing with and researching this subject for 25mos. Most of the answers have been given in the above replies, hopefully this adds to them? It appears GM set the Torque Converters to sliplock in these vehicles actually starting in 1st gear at a certain throttle position and speed, and starting with too low of a psi to actually attain lock. That combined with the fact that the JMBX TC they chose has a clutch plate and housing that don't mate up well. It's kind of like stacking two dinner plates of different design. Because of that the clutch material doesn't make contact across it's full width. Kind of like dropping the needle in the middle of the music grooves on an old vinyl and only ever playing that portion of the music. IMHO, either one of those flaws could've survived on its own but the combo causes the clutch material to wear off after 80-120k mi and eventually will cause the TC to grenade taking the tran, the lines and the cooler with it.

The quick answer is: It's only going to get worse as more and more of the clutch material wears off. With stock settings you can prolong the inevitable by driving in M5 with tow/haul mode engaged to prevent the TCC from trying to lockup -or- research the settings in either of these attached videos and set yours to what you're comfortable with.

I've emailed and spoken to engineers at Sonnax(multiple), GM, Lube Guard, and Valvoline. Spoken to local dealer$hip along with every trans shop in 50mi radius. Paid $93 for confirmation of problem to the only trans shop around me that was willing to do what I asked: confirm problem, if TC then replace TC, clean and inspect 6L80, add shift kit and add a few other upgrades I wanted in 6L80, and TUNE OUT the TCC lockup in the lower gears and raise the pressure when locking it. Turned out he wouldn't tune the trans after all...smh

In the last year or so I've noticed 6-8 new videos that ACTUALLY SHOW the fix, but none, IMHO, explain it as well as the original. I've got a folder with 12-15 of the best articles and vids I've seen on this subject, be happy to share more if you want? Here's the original vid and prob the best article describing the what's why's and how's of the problem and in the video, the HP Tuners fix used:

26min long but worth every second
https://www.youtube.com/watch?v=XnsdK2N2an4

excellent write up, must click on and enlarge pics to see
https://gearsmagazine.com/magazine/t...om-bob-warnke/

**This subject is how I found out HP Tuners exists and why I'm here. This is my 1st post lol.

Here's a vid I found the other day that may be more applicable to your solution? You may be early enough to not have to have overhaul on your trans? I would bet you are based on your descriptions of vibrations, but only you can decide that? Skipped through this guy's HPTuner settings, but I've watched Hiram's 5-6 times. I may even go one further than Mr Gutierrez and disable TCC lock in 5th gear also?

https://www.youtube.com/watch?v=sag3h2AQ2uU

Good luck and please follow up with what you do and the results....

[alabastarbastard]

try this out... this is on a stock 2016 5.3 silverado, runs amaizingly well for 80k miles

[alabastarbastard]

tcc pids for monitoring adjustments

i'll try and find the video walk thru on setting it up

[Scottyb_288]

been doing a ton of reading on 6l80 tuning since we bought my wifes 07 denali. im curious why 1.0 gain vs 1.5(factory setting on mine).

[alabastarbastard]

i'm guessing that the higher the gain number, the faster the ramp in time

i highly recommend purchasing the 6l80/8l90 tuning book from the tuning school for $180. at least you'll get an understanding of whats going on in there

[Scottyb_288]

I have a pretty good understanding of how everything works minus the pressure offset and pressure gain tables. Given that you said your guessing what it does, id assume the TTS book does not explain it? Which would not make it worth $180 to me.

[alabastarbastard]

there is still good info in the booklet that would make it worth the money, the $180 also includes tech support and help with questions you might have. that alone is worth more than a canned trans tuned. take it or leave it

merry xmas and have a happy 2023

[Scottyb_288]

I would never buy a canned tune. Ive followed the advice of many on here, including yourself, so far and the transmission is pretty much perfect to my liking now. Temps are well under control shift timing and feel are where i want them, but will continue to monitor everything and during the heat of the summer.

Thank you. Merry christmas and happy new year!

[alabastarbastard]

i noticed your line pressure is about 30-45 psi, increase the tcc pressure to about 60-70 psi

[Scottyb_288]

Where are seeing that? I assume you mean increase the TCC regulator offset to 60-70?

[alabastarbastard]

it was in the data log file