So I know this thread is pushing a year old at this point, but I am very curious if you've figured anything out on your truck? I just read through all the posts and I'm having nearly the exact same issues with my Denali. However it's currently tuned by Blackbear using EFI Live, and from what I can tell that means he does not have access to the desired slip tables. Brady at Circle D said that table needs to be zeroed out with their converters to prevent the shuddering/slipping, and I noticed you've already done that. I just picked the truck up last week after having a new 8l90 thrown in, and the converter was "refreshed" as well. I used Amsoil for the fluid.
I've ordered a MPVI2 to be able to make my own adjustments since Blackbear cannot so I'm very curious what you changed if you were able to correct it. Did you send off your converter to be looked at or have you been able to dial it in?
Last edited by DenaliStone; 03-08-2021 at 04:39 PM. Reason: Clarification
2016 GMC Sierra Denali | 6.2 | 8L90 | 4WD | Volant CAI | Kooks Headers | Magnaflow Muffler | E85 | Circle D Converter
The answer for the core issue of this thread is in the latest beta. It's a table called TCC Desired Pressure. The regulator offset/gain do not seem to work in this cal. Maxing out the apply ramp table doesn't work.... But whatever you put in that in desired pressure table, you get.
I just fixed a '16 1500 Circle D multi-disc truck's lockup today with it.
aww man. you got me so excited. that table still isn't there for a 17 camaro. i did download a tune for a 16 silverado with a 5.3 and a8 and sure enough it is right there but not for the camaro. i wonder if a fresh read would help.
2017 camaro ss a8 with low mount twins
2022 Cadillac CT5-V Blackwing (733 whp)
2022 Cadillac CT4-V Blackwing (716 whp), 10.750 @ 134.77 mph
2016 Cadillac ATS-Vs (eleven ATS-Vs in the 9s)
2008 Pontiac G8 (first G8 in the 10s), 10.727 @ 129.87 mph
2000 Bonneville SSEi (first 3800 Bonneville in the 10s), 10.711 @ 125.71 mph
1999 Grand Prix GT (first 3800 FWD in the 8s), 8.902 @ 154.90 mph
1998 Firebird (first 3800 RWD in the 8s), 843 whp, 8.991 @ 152.12 mph
1998 Grand Prix GTP (first 3800 FWD in the 10s), 9.499 @ 145.13 mph
Not yet... I'm still on it now.
I actually was one flash away from sticking a fork in it, and out of the blue, it does this things where it just hangs/ feel like neutral on a 1-2 shift and then BANGS into second gear. I actually did a full write back to OEM and it persisted. Then, I decided to try a fast-learn and ran that... it got MASSIVELY WORSE and it does it shifting into 6th gear now as well . It's so hard in 2nd gear that you have to idle out and let it shift and it STILL slams. I reset/preset OEM adaptives and it made no difference either. I'm about to re-do the fast learn and then try and hit the driving portions that learn specific clutches to see if it helps. I honestly have no idea what this thing is doing, and I'm not used to saying that...
But for lockup, I look a the desired pressure table in PSI. I set every cell under 45 PSI to 45 PSI. I set a lockup schedule that was just after the shift into 8th and it did exactly as expected... locked right up showing 45 PSI. I set the regulator offset and gain back to OEM and it made no difference; still locked up as I wanted with 45 PSI. I release just ahead of the gear drop on increasing throttle. It needs some fine tuning but it definitely works. No more dithering light pressure and slip in and out.
Also to note.... In both the regular desired slip and DoD Desired tables, I have all zero's. However, I see 3 RPMs and then 10 RPMs when logging desired TCC Slip. We don't GET any slip though, with min lockup pressure of 45 PSI. I have the TCC adaptives nixed by temp enable. So again, it doesn't actually slip, but the logged Desired Slip is not a zero value, despite it being that in the editor.
So Desired Slip, Regulator Offset/Gain... either aren't mapped right in the definition, or are not used, for whatever reason.
What I would LIKE to have access to, is the default adaptive values for each gear and the ability to also nix upshift adaptives from running.
Last edited by Frost; 03-19-2021 at 09:40 AM.
Can confirm from personal experience that the above mentioned desired pressure table also is the ticket for my Holden 6L90 where reg offset and gain have had no effect.
To keep it simple with my ride I grabbed the 5th column and shifted the whole table to the left. Then took 5% out of the first column at a time until I was happy with the initial apply NVH. Worked well for my single disc high stall.
Also noticed that the 4wd low apply ramp table also adjusts the way the TCC pressure is applied so there is something there to be investigated going forward.
Hello Mr Steve Williams @ Frost.com. I have a customer that has a 2015 Silverado High Country 6.2L with the 8l90. His torque converter shudders cruising at any speed under 72mph. It's the stock transmission & convertor. He has not had the flush and new Blue label fluid installed. I'm wondering if I raise his minimum tcc lock up pressures up to 45psi could it help his situation? I noticed that some of the people with this problem have already have had the flush & new fluid and their problem still exist. I noticed you mentioned DOD in your comments above. I did have to delete the DOD with a new from Texas Speed OEM non DOD with VVT camshaft, top plate and all other necessary delete components. I did deactivate the DOD in the ECM and deactivate all the DTCs for cylinder deactivation. Just hoping for a simple fix. Thanks Danny
Last edited by Danny Taylor; 04-06-2021 at 07:34 PM.
Hey Danny,
email me at [email protected] and I'll help you out with this / no bill.
2016 GMC Sierra Denali | 6.2 | 8L90 | 4WD | Volant CAI | Kooks Headers | Magnaflow Muffler | E85 | Circle D Converter
Sure; shoot me an email.
Exact same thing is happening in my 2012 Suburban 2500 6L90. To recap, is it confirmed the regulator gain and offset don't work? I was just about to go try bumping the gain up a little. And how can I get the min pressure table activated? I downloaded the beta but it hasn't shown up for me. Any help is greatly appreciate. I was about to swap my TC and start going crazy on this thing and then found these threads with others having a similar issue.
Last edited by snapback17; 06-01-2021 at 06:54 PM.
Sorry i know mine is a 6L90 not an 8L90. Hoping they both have this feature.. logs attached. I basically feel a shuddering at certain steady state points and during accelerations.
TCDebug1.xlsx
ok so i zero's out the slip tables and decreased the regulator offset to 0 (was at 180 kpa). I dropped it down by half first, then again. The last run had the best results for steady state. But, during accels, when it locks up in 4th, the TCC pressure starts to bleed off, then its too low when it shifts to 5th and loses control. You can see the steady state in the middle of the file and the acceleration at the end. Any suggestions to help this accel? That minimum line pressure table would be really handy right now...
Slip0RegMinus180_2.xlsx
Post your tune and the hpt log file. xlsx is a pain.
And try disabling TCC adapt. Just 0 out the adapt min and adapt max cells. See how that goes.
I got excited when I saw that this thread had been updated and realized this new TCC desired pressure table was added. Then I realized just like 90% of the other stuff we have for the newer GEN IV and V stuff it has 0 effect. I try to be patient and realize how difficult it is to basically reverse engineer this software so we can tune things, but I wish it would be more advertised as beta. I am thankful that at least the most important tables work like the VVE and air model stuff, its just frustrating to have the same problems year after year. I just put in a Circle D HP 1Y with the woven carbon lockup clutch in my 8L90 Camaro and I feel like I am just destroying the clutch and locally overheating it since I can see the pressure come on very slowly and slip comes down some but then kind of hangs and hangs and may eventually go to around 0 as long as there is light throttle.
Has anyone gotten anywhere on a 8L90 with this? I mean the TCC desired pressure does do something, after you change it you can see where it just edits back this "fake" "calculated" pressure but there is zero physical change to lockup.
Just curious, have you tried it with TCC adapts disabled?