Newbie asking for help with 8L90e tuning for TCC shudder New TC and Mobile 1 fluid

[pecothern]

I had an opportunity to buy cheap a 2015 Sierra Elevation edition 6.2 truck with the 8l90e. It had two dead misses and assumed dropped lifters plus the guy told me the transmission shuddered. I bought it cheap enough to do the repairs. I have a mechanic I trusted do the AFM delete new cam etc. engine is perfect. We replaced the torque converter aftermarket with stock specifications and refilled with the Mobile 1 synthetic fluid 16$ a quart. My guy also "tuned" the transmission. I will attach the tune. As I understand the Adaptive has been turned off essentially by raising the temp to 248 I believe. TCC lock has been enable in gear 6-7-8 only. Also he said he increased TCC desired pressure to a minimum of 90 "Pounds" he said pounds but the table list it as KPA. 90KPA is only about 13 pounds. Also he said he change slip to zero. I'm sorry if I'm using the wrong terms. I am experiencing shudder when driving using my Autel scanner MK808BT Live data as the TCC solenoid is energized it ramps up and between 20-30 psi shuddering occurs with 40-60 slip. As pressure rises above 30, lock occurs with 0 slip. This makes me think the Torque converter is ok. I thought about taking to dealer for triple flush. But they quoted me 700$ I'm thinking for that price I could buy hptuners myself and exchange the fluid 6-8 quarts at a time a few times and see if I could tweak the transmission into driving as I like.

I am nervous and want to avoid the shudder that could damage the Torque converter and that trash could damage transmission. I also have a 2013 Camaro with 6.2 and 6L80e I can use hptuners on in the future. I have ordered the new interface. for now I am using version 4.10.7 but expect to upgrade to latest when I get the new interface. I have done the EPA review and tests. I have a few questions before I touch anything.

Since Adapt is essentially disabled by the high temp will I or should I try or be able to do the fast learn procedure?

Should I try to find the stock tune on the 8l90e and reflash and try fast learn and start from scratch ?

If I slip and shudder below 30psi should I increase the desired pressures to a minimum of KPA that is = 30 psi?

I have planned to bypass the thermostat as transmission seems to behave better and shudder less when cooler. I figured I'd lose a lot of fluid when I do that and that would be my first partial exchange flush. I've ordered 10 quarts. This sound like an ok idea?

Please take a look at attached tune below I believe the engine and the transmission are in it. I'm ok with everything about this transmission shift behavior except the torque converter shudder. LMK anything crazy or doesn't make sense
The guy that tuned it builds engines not transmissions

Thank you so much for your time. I am retired now and pretty handy. Have been interested in learning some simple tuning for awhile as a hobby.

[Roller75]

Looks like the desired slip tables are zero'd which is the main thing. The TCC pressure section is fine as well as the apply/release tables. Just need to re-enable the TCC adapt portion. Basically the desired slip tables are the target slip and yours is zero so it will shoot for zero slip RPM. The TCM will adjust to that target if it sees slip above that desired number similar to short term fuel trims. The TCC Adapt portion is like the long term fuel trim of trans slip. So when it's enabled it knows, last time I was in this situation I needed to add 5 psi to hit desired slip, so it will start with 5psi more trying to maintain that target zero slip. If you enable the TCC adapt you should be good. Just do a Trans Adapt Reset and take it out for a drive, no need for a fast relearn.

As for the thermostat delete you will lose virtually no fluid pulling the housing off of the transmission. Maybe a couple ounces. Just pull the lines out and then unbolt from the transmission, take it to the bench, take out the snap ring, dump the guts, install your kit and reverse for installation. Easy peasy.

Good Luck!

[pecothern]

Looks like the desired slip tables are zero'd which is the main thing. The TCC pressure section is fine as well as the apply/release tables. Just need to re-enable the TCC adapt portion. Basically the desired slip tables are the target slip and yours is zero so it will shoot for zero slip RPM. The TCM will adjust to that target if it sees slip above that desired number similar to short term fuel trims. The TCC Adapt portion is like the long term fuel trim of trans slip. So when it's enabled it knows, last time I was in this situation I needed to add 5 psi to hit desired slip, so it will start with 5psi more trying to maintain that target zero slip. If you enable the TCC adapt you should be good. Just do a Trans Adapt Reset and take it out for a drive, no need for a fast relearn.

As for the thermostat delete you will lose virtually no fluid pulling the housing off of the transmission. Maybe a couple ounces. Just pull the lines out and then unbolt from the transmission, take it to the bench, take out the snap ring, dump the guts, install your kit and reverse for installation. Easy peasy.

Good Luck!

Thanks Roller75 If I understand you correctly ? you believe I should reenable TCC adapt and all have to do to make that occur with my current tune is change the minimum from currently 248 back to maybe 68? and Flash this back to the TCM of course. Then use my scanner or hptuners to do a trans adapt reset then go drive it a bit? Sound about right ??

[Russ K]

I set up the Torque convertor pressure & lock-up speeds. I don't have the same OS to see if the TC apply ramp is stock, so return the ramp table to stock.

Russ Kemp

[pecothern]

I set up the Torque convertor pressure & lock-up speeds. I don't have the same OS to see if the TC apply ramp is stock, so return the ramp table to stock.

Russ Kemp

Thank you Russ!

[1scls1z]

I would reenable TCC adapt and see what happens.

[Roller75]

TCC Adapt.jpg

Yep,

This is from an 8 speed truck I did earlier this week. Stock adapt settings

[pecothern]

TCC Adapt.jpg

Yep,

This is from an 8 speed truck I did earlier this week. Stock adapt settings

Thank you Roller75 Just got my interface in yesterday Gonna try to get on this next week Phillip

[pecothern]

I set up the Torque convertor pressure & lock-up speeds. I don't have the same OS to see if the TC apply ramp is stock, so return the ramp table to stock.

Russ Kemp

Huge Shoutout to Russ-K !!! your tune was exactly what made my truck worth keeping and not a huge mistake purchasing .I read a post the other day a guy got rid of a $70,000 Yukon that had this shuttering problem since almost new. I am very pleased, My torque converter now reminds me of my old 83 Camaro, Locked or unlocked.... nowhere in between. I understand the "theory" behind keeping pressures low and decreasing parasitic loss from the pump. Even in theory the soft engagement and disengagement for improved NVH. My truck was shuddering into lockup and out of lockup every time, every shift from 6-8 and back down to 5th. This after replacing the torque converter and using the new expensive fluid Mobil one. I guess GM cannot flash a tune like this into these trucks because it may negatively impact MPG and EPA would be all over them??. But hell my truck.. weighing 5500 pounds with a 6.2 and AFM deleted and 35" tires posted 24.7 avg MPG at 60 mph with cruise on for 25 miles. My jeep with a 3.6 V6 and 4 speed automatic is a turd that cant get out of its own way going downhill and gets 14mpg if your lucky. Do I want to get 1 more mpg and spend 6 or 7000$ on my transmission every 70 to 80k miles Hell no. If I understand properly The 8 speed trans is pretty good they get trashed by the torque converters. With Russ' tune I even went in and added 5th gear to lockup now I have lockup happening in 5,6,7 and 8th. THIS SEEMS TO HAVE FIXED ALL MY SHUDDERING PROBLEMS! How has this not gone viral? Everyone with this issue should be applying these parameters.... zero slip every time. amazing. I am seeing pressures 40-55 now... before I was seeing 20-40 every time pressure dropped below 30 I'd see slipping and feel shuddering. Russ I am so thankful you took the time to give me some guidance. I would be happy to pay you for your time. I have read many other of your posts and I am very impressed by your knowledge and willingness to help people. Thank you again Phillip

Ps : Russ I sent you a PM

[DenverII]

Russ K, do you offer remote tuning services?

[67firebird455]

I just wanted to take a minute to stop by and thank RussK for the file he shared. My 2015.5 Yukon XL Denali (A8) started shuttering years ago, they replaced the fluid a few times since the original fluid was hydrostatic, the shuttering went away. It has since returned since we've got just over 140,000 on it now, and your TCC changes and unlock/lock settings made this a whole different car. My wife just took it for a drive and was blown away saying it's never driven like this. Thank you again for your commitment to the community! A lot of us guys sure appreciate it!

[pecothern]

I just wanted to take a minute to stop by and thank RussK for the file he shared. My 2015.5 Yukon XL Denali (A8) started shuttering years ago, they replaced the fluid a few times since the original fluid was hydrostatic, the shuttering went away. It has since returned since we've got just over 140,000 on it now, and your TCC changes and unlock/lock settings made this a whole different car. My wife just took it for a drive and was blown away saying it's never driven like this. Thank you again for your commitment to the community! A lot of us guys sure appreciate it!

67firebird455 are you saying you used the tune Russ sent me to fix my Sierra to fix your wife's Denali? If so that is crazy awesome. BTW its been a little while but I did go back in and change some settings to let it lock up in 5th also. Pretty sure Russ' had it locking up in 6,7,8, only. I just thought I'd push it a little more and see what happened. I only detect the slightest bit of shudder every once and a while. I wonder if turning adapt back on has allowed the transmission to wander back toward old settings? I notice this too after driving it long distances "hours". I've thought about reflashing and turning adapts off. I'm planning on dropping the pan and replacing the fluid again and I bought the device that bypasses the transmission thermostat. Seems like it shifts better and less likely to shudder when it's cooler. Gonna do that soon.

One question, when you said fluid was hydrostatic did you mean hygroscopic ? like it had moisture in it? BTW curious also have you had your air conditioner condenser fail? Lost freon ? I'm changing mine right now that's why I thought it would be a good idea to replace the fluid now since the trans cooler is in the condensor.

[isaihelgaaen]

I too dropped Russ?s tune into my 2016 Yukon Denali 6.2 8L90 and it seems so be good so far. I only drove for about 20 minutes after flashing but I only noticed that 1-2 2-1 hard shift one or two times? I haven?t told my wife how much better I thought it was driving yet, so we will see how she reacts tomorrow and will update. What?s the benefit to turning the lockup back on 5th gear may I ask?

[isaihelgaaen]

I too dropped Russ?s tune into my 2016 Yukon Denali 6.2 8L90 and it seems so be good so far. I only drove for about 20 minutes after flashing but I only noticed that 1-2 2-1 hard shift one or two times? I haven?t told my wife how much better I thought it was driving yet, so we will see how she reacts tomorrow and will update. What?s the benefit to turning the lockup back on 5th gear may I ask?

Update:: I flashed the exact tune he provided for your sierra into my Yukon. I drove around a bit last night and after about 20 minutes it seems most of my hard shift was gone. I went and compared files to my stock ECU tune and changed a few things back to stock like the intake came angel above 5,200 RPM, but I left the engine torque tables updated cause it seemed like mine was wayyyyy under tuned? Flashed it this morning, but my wife says the transmission is still hard shifting between 1?2. Possibly because I didn?t drive it after I reflashed this morning before I left? I?m willing to provide my stock tune (DOD disengaged) when I?m home so someone can compare and maybe help me decide if there?s a few more parameters I should change relating to my specific hard shifts.
I?m currently running RussK?s tcm tune he wrote for this 15 sierra, and the ECU tune for the sierra with a few things changed back to stock for the Yukon. I?m gonna compare stock tcm files when I?m home and see exactly what he?s changed and maybe changed just a bit more to try and eliminate that hard shift. TIA

[pecothern]

I too dropped Russ?s tune into my 2016 Yukon Denali 6.2 8L90 and it seems so be good so far. I only drove for about 20 minutes after flashing but I only noticed that 1-2 2-1 hard shift one or two times? I haven?t told my wife how much better I thought it was driving yet, so we will see how she reacts tomorrow and will update. What?s the benefit to turning the lockup back on 5th gear may I ask?

I believe the initial setup has it locking up the TCC even in 2nd gear up to 8 , I think theoretically the more it's locked up the more efficient and less slip there will be and therefore lower RPMs and better MPG and less heat production in the TCC. Just a guess. I believe everytime it shift it unlocks....shifts ....then relocks Mine used to shudder in and shudder out every shift but now its way better and see on my scanner the slipping is almost 0-10 rpm all the time. Lets remember all that slipping in and out makes the shift smoother.... IF its not shuddering. I'd rather have the harsher lockup than deal with the shuddering. PS Have you noticed you can essentially cancel out and adaptive stuff the trans does by raising the temp higher than it will ever get before it will start adapting?. That basically deletes all the adaptive stuff from happening Phillip

[ltemup4650]

@RussK

Greetings. I tried to send you a private message as to not bump this thread but your inbox is full. Popular guy!
I have a 2016 Buick Enclave (3.6L with 6T75 transmission) that has developed a torque converter shudder. The shudder happens in lower speeds, light acceleration, and under load (going up hill). I replaced the valve body and installed some instant shudder fix fluid additive (friction modifier), The shudder is about 50% better, but still most definitely there.

My tuning experience is very basic (turn off VATS and DOD etc.)

I’ve been doing some research on tuning the TCC and found this thread.

Question: If I send you my tune file in the next few days, would you be willing to do the same/similar changes to make my TCC not slip (reduce or eliminate shudder by adjusting pressure & lock-up speeds).

Of course I am more than willing to pay you for your time.

Thank you for your consideration.

[Russ K]

Post your tune & question in the V6 Trans section and I’ll take a look at it.

Russ Kemp

[ltemup4650]

Excellent. In a couple days, I will do that. Thank you!

[ltemup4650]

Post your tune & question in the V6 Trans section and I’ll take a look at it.

Russ Kemp

Hello Russ. Here it is:
https://forum.hptuners.com/showthrea...5-Transmission

[isaihelgaaen]

I believe the initial setup has it locking up the TCC even in 2nd gear up to 8 , I think theoretically the more it's locked up the more efficient and less slip there will be and therefore lower RPMs and better MPG and less heat production in the TCC. Just a guess. I believe everytime it shift it unlocks....shifts ....then relocks Mine used to shudder in and shudder out every shift but now its way better and see on my scanner the slipping is almost 0-10 rpm all the time. Lets remember all that slipping in and out makes the shift smoother.... IF its not shuddering. I'd rather have the harsher lockup than deal with the shuddering. PS Have you noticed you can essentially cancel out and adaptive stuff the trans does by raising the temp higher than it will ever get before it will start adapting?. That basically deletes all the adaptive stuff from happening Phillip

Oh yes, I took the last week or two and did a lot of research. Even wrote a few different tunes. Transmission is doing MUCH better as of today lol. Better shift times, hard lock ups, better pedal reaction, more timing. She feels like a whole new truck.