6l80 tcc slip tuning stock clutch

[Charlie207]

Indeed, especially when you consider that 6L90s work a helluva lot harder than 6L80s,
and yet somehow last longer ...

Tuning aside, arent the 6L90s physically larger than 6L80s? I read somewhere they are 2" longer.

Wouldn't surprise me that they engineered the 80 smaller to juuuust barely last long enough, in order to save a few bucks.

 

[Marky Dissod]

Tuning aside, arent the 6L90s physically larger than 6L80s? I read somewhere they are 2" longer.

Wouldn't surprise me that they engineered the 80 smaller to juuuust barely last long enough, in order to save a few bucks.

The physical size difference is minimal. What's far more important:
The 6L90 is built to withstand more torque and RpMs (some of that extra size is internally important, some of it is just case strength)
GM OE 6L90 2500 tuning, not just TCC behavior, sacrifices a wee lil bit of NVH that your wife might whinge about, for durability & longevity towing & hauling

 

[NickTransmissions]

Tuning aside, arent the 6L90s physically larger than 6L80s? I read somewhere they are 2" longer.

Wouldn't surprise me that they engineered the 80 smaller to juuuust barely last long enough, in order to save a few bucks.

You're correct, the 90s are about 4-5 inches longer and those that went into diesel-equipped vehicles had an extra clutch and steel in the packs as well as stronger planetary carrier sets and the TMBX converters they came with had flanged hubs whereas the 80s converters did not. It's a stronger transmission all around, especially the diesel versions but it also suffers from the same general pattern failures/issues as the rest of the 6L family, particularly the 6L80.

 

[Marky Dissod]

It's a stronger transmission all around, especially the diesel versions -
but it also suffers from the same general pattern failures/issues as the rest of the 6L family, particularly the 6L80.

Is it a a safe guess that most 6L90s also work harder than most 6L80s?

I'm GUESSING that if a 6L90 lived the gentler life of a 6L80, the 6L90 might tend to last longer than the 6L80?

PLEASE, let me know if I'm guessing wrong here ... ?

 

[NickTransmissions]

Is it a a safe guess that most 6L90s also work harder than most 6L80s?

I'm GUESSING that if a 6L90 lived the gentler life of a 6L80, the 6L90 might tend to last longer than the 6L80?

PLEASE, let me know if I'm guessing wrong here ... ?

That's impossible to say unless you either take surveys of sufficient sample sizes to draw such conclusions or the data is already out there, plus you'd have to quantify what it means to 'work harder' to ground the results.

Bottom line: they are all prone to the same type of failures, most of which involve the torque converter so it wouldn't matter how strong one variant of that transmission family is relative to the others if the converter's poor design is driving the majority of the breakdowns.

 

[Marky Dissod]

... quantify what it means to 'work harder' to ground the results.

Most 6L80 vehicles are personal transit appliances Towing / Hauling less weight less often compared to 6L90 vehicles which tend to be workhorses ... ?

 

[B-train]

I had the 6L90 in my 2015, 3500hd work truck. I absolutely loved that transmission. The torque converter did fail at 50k though (both 2015 trucks failed at similar miles?? The 2017s didn't have issues) It was replaced and then gave another 115k of additional service without 1 issue before being traded out. It was a heavy truck - 12k all day, everyday, and then pulled an 8k trailer a couple days a week.

The trans calibration was right on the money in my book. I'd take one of those anyday. And, it was driven in Chitcagoland it's entire life. That's probably the best drivetrain in my book - 6.0L with 6L90

 

[Foggy]

They also used the 6L90's in the cadillac ctv-s supercharged 6.2L
They are supposed to hold a little more torque , hence 90 vs 80
I thought some parts were interchangeable on these and the size diff
was like 1 inch or so... I've never physically touched a 90E
I imagine the "tuning" programming parts is really similar with TCC slip
patterns/numbers

 

[LSCALADE]

I used CHAT GPT to teach me about the functions of the table. I had a lot of tough questions and back and forth it seems GPT 5 is able to deeply understand what happens with each table if the values move up and down.

My trans was set to GAIN 26psi and Offset of 1.5.

I kept moving the pressure slightly as well as the apply ramps to grab a slip and control it quickly and I got pretty far after 30+ adjustments but it always would get to a load situation up a slight hill and above 25% throttle it would slip and shudder.

Shudder is bad, we know it causes material wear from whats left at least. One fix for that is to let go of the TC clutch above that % throttle and it worked, the TC unlocks and it feels like a half gear downshift. But still it would randomly shudeer outside that window and finally I asked how do I stop it compleetly.

It made me bump the GAIN to 88psi, and offset to 1.5.
It also asked me to adjust desuired pressures in the mid table.
Apply ramps were tweaked a little bit and now I have a good positive locking TC.

This will allow me to make it a little longer before I get CTS V converter installed. So far I am happy with it. I can share the files if anyone is interested.

 

[mikez71]

It made me bump the GAIN to 88psi, and offset to 1.5.

Interested in seeing your changes! But I think you mean offset 88psi and gain at 1.5?
The one time I changed gain, it felt funny so I never tried it again.

I don't like feeling TCC engagement, but the stock tune does take awhile to lockup... and not completely.
For awhile I ran reduced slip, but lately I've just been running stock settings.

I've been thinking about disengaging the TCC earlier to get that 'half gear downshift' effect you mentioned.
Though it seems like it always downshifts 2 gears when I press the pedal. 4-2 or 5-3.. or 5-2..
People say it's bad to just mash the pedal when you're cruising along.
I wonder if turning off 'skip downshift' would help preserve the transmission?

 

[LSCALADE]

Interested in seeing your changes! But I think you mean offset 88psi and gain at 1.5?
The one time I changed gain, it felt funny so I never tried it again.

I don't like feeling TCC engagement, but the stock tune does take awhile to lockup... and not completely.
For awhile I ran reduced slip, but lately I've just been running stock settings.

I've been thinking about disengaging the TCC earlier to get that 'half gear downshift' effect you mentioned.
Though it seems like it always downshifts 2 gears when I press the pedal. 4-2 or 5-3.. or 5-2..
People say it's bad to just mash the pedal when you're cruising along.
I wonder if turning off 'skip downshift' would help preserve the transmission?

Sorry Yes, I got those flip flopped.

You need to log it but I would imagine when it sees something like 70% throttle it says ok it needs a downshift and it drops it to the gear below.

But if you are cruizing down the highway at 20% throttle doing 70mph and you tip in say 40% throttle you can tell it at 35% throttle and above to lock the converter at 100mph so when you step on it and you cross the threshold it will unlock the converter and stay unlocked in 6th gear until you reach the next threspoint for downshift. Its actually quite nice.

 

[mikez71]

Neat, so lower numbers on tcc apply ramp is more aggressive?

Also notice you lowered TCC max allowed pressure?
(Or perhaps your model was setup different, my stock 5.3 is set at 138.22psi where yours is at 128psi)

 

[Marky Dissod]

... lower numbers on tcc apply ramp is more aggressive?

Yes.
Zero ramp = instant sudden application of full force (a sweet snappy punch that moves the jaw before the skull or neck can follow)
More ramp = gradually progressive application of increasing force (push your kid on the swing hard but they love it because they go even higher)

Or:
Zero ramp = smack the throttle suddenly, break the tires loose, go nowhere awesomely (which may actually protect transmission innards)
vs
More ramp = roll into the throttle with a smooth quickness that gets the vehicle going with a tire chirp at most that gets you in front of the slowpoke at your flank

 

[Charlie207]

Is there a way to link shift patterns (sportier) with the the transmission modes (Drive vs. Manual Mode) to tell the TCM to only downshift one gear, or stay in the selected gear as I apply more throttle?

I feel like my 6.0L engine has more than enough torque to maintain speed up slight inclines without stressing the transmission internals, but it loves to downshift at the slightest throttle input. If I was in a vehicle with a manual transmission I'd just leave it in the same gear, and let the engine do the work it was upgraded to handle, with ease.

This seems really annoying at low speeds when I'm just trying to nudge the throttle a little bit, but ECM & TCM are constantly in full-kill mode... and drop two gears while revving to 4500rpms, just to make a quick lane change.

Or, is the factory brain-box just not able to run something that sophisticated?

 

[Marky Dissod]

Manual mode is just using the shifter in 'M'. Manual modes can also be tuned to a lesser extent, but generally, if you command a shift into whatever gear,
only reason why it'd shift out of the gear you commanded is because a) tcm thinks you chose poorly, b) tcm trying to protect 6L80 from excess heat, c) a & b.

In your case (already tuned by BlackBear), practice driving as daisy as reasonably possible for 1 or 2 days.
Get BlackBear to send you the kit that'll let him watch you drive daisy, tell him you want as few unnecessary shifts as reasonably possible at those daisy TPS angles ...
in 'Normal' Mode. That way, you know it'll be conservative when your foot is conservative.

(Back when I had an LT1 Caprice wagon, since it was unable to access a 2nd shift mode,
I basically made my one 'Normal' shift mode look like 'Dr Jekyll' under 31% TPS,
transitioning between 31% & 36% TPS, fully 'Mr Run&Hide, itches!' by 37%TPS.)

It's up to you if pressing the thumb-button on the shifter makes it act like 'Tow / Haul' mode, or 'Performance' mode.
Since I'll likely never attach anything to my tow hitch, my 'Tow / Haul' mode is reprogrammed to behave like a 'Performance' mode.
I've a spare pcm where 'Normal' mode assumes I'm hauling 1800lb inside, and 'Tow / Haul' mode assumes I'm towing 7500lb.

 

[mikez71]

Most all settings are the same between normal and tow mode. It's only the shift speed's that are changed. (or at least all we have access to..)

I know the feeling, you just want to nudge a little, and it downshifts. You ease off, it upshifts. All you did was flare the rpms for a few seconds..

You can make downshift speeds low/flat at lower tps%, so it will stay in gear easier, allowing you higher throttle angle before downshifting.
Adjust it too far, and you have to really get on it to downshift.

 

[Marky Dissod]

Most all settings are the same between normal and tow mode. It's only the shift speeds that are changed (or at least all we have access to ...)

There are provisions in the GM OE tune that (luckily) increase applying and holding line pressures in Tow/Haul mode,
on top of the fact that line pressures are 'designed' to increase as MAF readings / MAP readings / TPS readings increase.

Which 'main' line pressures, or line pressure 'modifiers' are available depends on the depth & breadth of the definition file available.

 

[mikez71]

I was looking at 6l80 having same settings in normal and tow mode..
That is not including portions of OE tune not shown by HPTuners of course.

Looking at a 4l80 tune, there seems to be more differences between normal and tow mode.

 

[B-train]

@Marky Dissod did you change parameters in the torque management section as well? I haven't delved into that yet, but have made conservative changes on my 2008 Denali, 6 speed.

1. Lessened TCC slip by about half across the normal range. I compared a file from a 2015 HD truck with the 6L90 as a reference.
2. Played with the speed (mph) tables to get it to shift at the speed I want which has resulted in a very nice driving experience.

I'd like to know more about torque management and what I can turn off to just not have the nanny over my shoulder all the time. I do drive quite conservatively most of the time.......racing is too expensive, in many ways.

 

[Marky Dissod]

I was looking at 6L80 having same settings in normal and tow mode ...
That is not including portions of OE tune not shown by HPTuners of course.

Looking at a 4L80 tune, there seems to be more differences between normal and tow mode.

Certain vehicle platforms have more thoroughly defined 6L80 parameters than others, like 'vette & Holden-based platforms.
4L80Es got pretty well defined across the vehicle platforms that used it (including Rolls Royce / Bentley Motors, Jag, & Aston Martin).

@B-train, can't say for sure if my tuner turned off Torque Mgmt in the 2012 Yukon XL I leased, but I'd borrow a lot to bet he did;
after he tuned it, every shift took less time to complete and had a lil nudge / bump to it which changed in character depending on how I was driving at the moment.

If you're willing to, you can just use 6L90E TCC slip settings. You'll physically notice the TCC apply / release each time, but it'll last longer as a result.

(One of the very few vehicles he went out of his way to mention that you should NOT turn off TrqMgmt, was the TrailBlazer/Envoys.)