6l80 tcc slip tuning stock clutch

[mikez71]

Found some interesting info on hptuners forum from Robert at Transgo...

"As for making it not slip the converter clutch in 5th and 6th that's mostly only good for aftermarket converter that don't use the GM woven carbon lining and so prone to shudder. The carbon woven lining is very brittle and designed to slip without wearing out, but it is super brittle . the extra pressure required to make it not slip and the increase rate of apply is ******* it and it often will crack and lose chunks of it causing the TCC to start slipping after many thousandths of mile with this modification. Eliminating lock up in 1-2-3-4 is not going to hurt anything, but I would not recommend increasing the pressure to stop it from slipping the 20 or so RPM factory programing does."

Little more info here...

2010 Tahoe with 6L80, tune for longevity and towing

I have a 2010 Tahoe 5.3 (LMG) with the HD trailering package (8200lb rating) and occasionally tow a 7500lb trailer. It has 170k miles and is currently running and shifting well. I recently purchased an MPVI3 for this vehicle and want to do the following: -Disable AFM -Disable flex fuel. I only...

forum.hptuners.com

 

[Marky Dissod]

Is this worth anything?

6L80's eating converters issues. Anyone else?

www.silveradosierra.com

 

[strutaeng]

Found some interesting info on hptuners forum from Robert at Transgo...

"As for making it not slip the converter clutch in 5th and 6th that's mostly only good for aftermarket converter that don't use the GM woven carbon lining and so prone to shudder. The carbon woven lining is very brittle and designed to slip without wearing out, but it is super brittle . the extra pressure required to make it not slip and the increase rate of apply is ******* it and it often will crack and lose chunks of it causing the TCC to start slipping after many thousandths of mile with this modification. Eliminating lock up in 1-2-3-4 is not going to hurt anything, but I would not recommend increasing the pressure to stop it from slipping the 20 or so RPM factory programing does."

Little more info here...

2010 Tahoe with 6L80, tune for longevity and towing

I have a 2010 Tahoe 5.3 (LMG) with the HD trailering package (8200lb rating) and occasionally tow a 7500lb trailer. It has 170k miles and is currently running and shifting well. I recently purchased an MPVI3 for this vehicle and want to do the following: -Disable AFM -Disable flex fuel. I only...

forum.hptuners.com

Thanks for sharing! I'll read it in more detail later.

So I think he's saying in his opinion eliminating the TCC slippage doesn't hurt, but don't mess around with pressures and such on a high mileage vehicle in OP's case? And doesn't do anything to prolong the life of the original torque converter clutch, but there's better shift feel? Umm...

We have a low mileage family van with the 6L90e, and I was going to buy the HP credits to eliminate the TCC slippage this year, "just 'cause everyone recommends that"... luckily it doesn't have DOD AFM stuff...

My wife drives that van, every now then I'll drive it if we are all going somewhere. I honestly still prefer my 'ol suburban or other trucks with the ancient 4L80e

BTW, my buddy suggested I join the HP Tuners forum. How is it there? I'm not much of a "Tooner" though. IDK

 

[Marky Dissod]

my buddy suggested I join the HP Tuners forum. How is it there? I'm not much of a "Tooner" though.

Since the forum is run by HPTuners, some tuning subjects you can't discuss, some only after taking a course or some humbuggery ...
They wub acronyms and jargon, moreso than normal
You know how most doctors tend to say
Non-ST-Elevation Myocardial Infarction / NSTEMI
before they say
heart attack?
It's like that over there too.

 

[mikez71]

Well the hptuners board seems to deal with mostly performance tuning, removing MAF, programming segment swaps and so on. I just scour it for general gen 4 and 6l80 tidbits.

Transgo Robert seems to indicate that zeroing slip on stock tcc will require a bump from ~40psi to ~60psi, and that the way the factory setup was designed, its just not meant to fully lock. Conversely the aftermarket clutches would prefer to fully lock or they may shudder.

Also something about a PR valve (pressure regulator?) wearing out being the main issue that kills them. Some photos in that linked thread, but havent been able to look at it yet..

Personally, I like the locked feel, but eliminated it in 1-3, felt 4th was worth it for slow cruise and really just get tired tweaking shift points and trying to get the corresponding lockup map in sync. I did notice some tuning changes in the 2015 tahoe with the 6l80 (like it always is locked in higher gears, flat graph. its on at x speed and off at y speed. ) Sometimes the tcc lock speed is below the shift speed, so it must lock right away, whereas my 2012 usually has the tcc lock 2mph or so after the shift. I also heard somewhere that the 2015-2018 6l80 does not last as long as the previous years...

 

[swathdiver]

I also heard somewhere that the 2015-2018 6l80 does not last as long as the previous years...

That's because of the thermostat they have. Runs hot all the time, converter flexes and clutch material breaks off and runs through entire trans.

 

[mikez71]

Only thing is, many of us don't have an aux cooler and the radiator would tend to heat the fluid higher than the thermostat temp. Unless of course the thermostat sticks..

Little update, Transgo Rob feels like the later 6l80's seem to last a little longer than previous gens. I'm sure nobody has complete numbers, and that was his impression (which I'm sure can depend on the area, shop, number of newer vs older vehicles etc.) He also does not think the tune differences affect anything other than fuel economy..

Here are Robert's photos of the PR valve wear since you need to login to view pictures.

 

[Just Fishing]

I'll note that I tried disabling the tcc lockup in the lower gears, it made it drive better, more pep.
but my mileage went to shit, and my transmission fluid temps went up a bit!

I made some minor changes but kept the lockup in the end.
Now tow mode I had more fun and got rid of most of the lockup, but kept it in 6th.
That allows me to switch back and forth while watching the temps.

My converter also isn't stock, it's a double disk circle d unit with a slightly higher stall.

I also reduced overall allowed slippage by 50%

 

[89Suburban]

@NickTransmissions

 

[Marky Dissod]

Torque Converter Clutch lockup improves MpG and lowers ATF temps when the vehicle is being driven gently ... up to a point ...

Prior to '95, TCC locking was On or Off, which came with little gentle thumps - enthusiasts don't mind them, pensioners do though (?).
GM started Pulse Width Modulating the TCC since '95 to try to satisfy NVH targets, sacrificing some of the TCC's durability / longevity.

I made some minor changes but kept the lockup in the end.

How much of it did you keep, vs how much you did not?

 

[NickTransmissions]

Only thing is, many of us don't have an aux cooler and the radiator would tend to heat the fluid higher than the thermostat temp. Unless of course the thermostat sticks..

Little update, Transgo Rob feels like the later 6l80's seem to last a little longer than previous gens. I'm sure nobody has complete numbers, and that was his impression (which I'm sure can depend on the area, shop, number of newer vs older vehicles etc.) He also does not think the tune differences affect anything other than fuel economy..

Here are Robert's photos of the PR valve wear since you need to login to view pictures.

View attachment 420766
View attachment 420767
View attachment 420768

He's right as there were numerous updates that made it into the later models to help directly and indirectly with mitigating the various failure-prone areas in these transmissions. The lion's share of the changes were made between 2009-2012, with a few more in the following couple years.

That said, there were NO changes to the pressure regulator valve or torque converter clutch, which is a glaring omission on GMs part IMO. Both Transgo and Sonnax address the PR valve (as well as many other hydraulic issues) with their respective kits; no 6L should be rebuilt without installing one of those kits.

 

[Just Fishing]

I took my allowed slippage down by 50% but kept it.
Most will reccomend that you put it at 0, but i just took the allowed slippage RPM and cut it directly in half.
I think it was default at 20rpm, and I made it 10rpm.

Note that on that the thread they mention that reducing that is also equivalent to raising pressures.

I had some thrust bearing issues early on, so I got really careful around converter pressure settings + I have a double disk aftermarket converter...

I doubt any of it was related, but what a pita that was.

For the lockup settings, I tweaked some of the mph settings to my liking (raising the mph a little higher to prevent lockup until later).

 

[Just Fishing]

Found some interesting info on hptuners forum from Robert at Transgo...

"As for making it not slip the converter clutch in 5th and 6th that's mostly only good for aftermarket converter that don't use the GM woven carbon lining and so prone to shudder. The carbon woven lining is very brittle and designed to slip without wearing out, but it is super brittle . the extra pressure required to make it not slip and the increase rate of apply is ******* it and it often will crack and lose chunks of it causing the TCC to start slipping after many thousandths of mile with this modification. Eliminating lock up in 1-2-3-4 is not going to hurt anything, but I would not recommend increasing the pressure to stop it from slipping the 20 or so RPM factory programing does."

Little more info here...

2010 Tahoe with 6L80, tune for longevity and towing

I have a 2010 Tahoe 5.3 (LMG) with the HD trailering package (8200lb rating) and occasionally tow a 7500lb trailer. It has 170k miles and is currently running and shifting well. I recently purchased an MPVI3 for this vehicle and want to do the following: -Disable AFM -Disable flex fuel. I only...

forum.hptuners.com

some of the best info I have seen so far.
When I was wiping out thrust bearings in my engine, it seemed like it lasted longer if I kept the slip at 20 rpm
In the end I reduced the overall pressure by 5% and reduced the slippage to 10rpm.

I felt like I was nuts there for a bit (more than the usual amount ).

 

[mikez71]

Here are some of the differences between my 2012 vs a 2018 silverado 5.3 stock tunes.
Loading a compare file in hptuners does not work properly, some tables have different number of cells and not all options are available for both.

regulator gain 1.500 -> .375 ('use regulator settings' is not selectable on the 2018, so there may be some difference in the way gain value is used..)
min slip AC on 9rpm -> 3rpm
tcc apply release, mostly completely flat in the 2018, curves on the 2012.
tcc desired pressure completely different values, could be software is incorrect, or the values are processed differently..

Above is stock 2012, TCC slip is same for 1-3 (AC OFF 1st gear shown), same for 4-6 (below 1st gear graph, window name is blocked off, 5th gear shown)

Looks like the 2018 zero's slip at higher torque and reduces slip at higher rpms..

below is 2018, TCC slip 1-6 all the same (1st and 5th shown)

 

[mikez71]

I set my gain to .375 and also lowered my slip tables drastically, which did not feel right.
reset slip tables to stock 2018 settings and set gain to 1.0, which feels fine, possibly faster lockup?
I think having no slip at low torque settings, plus the .375 gain made the TCC lock/unlock very noticeable, not smooth.

Some TCC regulator gain info below from tre-cool at efilive forums. (may not apply to other OS's)
Apparently Bing AI has regulator gain backwards...
======================================

here is 1 i did for os 24256025
[D9790]
; Description
; ---------------------------------------------------------------------------------------------------------------------------------
DESC.001 = Selects the Gain of the TCC Pressure Regulator Valve.
DESC.002 =
DESC.003 = The OEM default is typically set to 1.500.
DESC.004 =
DESC.005 = Setting this to 0.000 will cause maximum pressure at all times, while setting to 8.000 will cause the TC to NEVER lock up (no pressure).

[D9795]
; Description
; ---------------------------------------------------------------------------------------------------------------------------------
DESC.001 = Selects the Offset of the TCC Pressure Regulator Valve.
DESC.002 =
DESC.003 = The OEM default is typically set to 26.69 PSI (184.0 kPa).

 

[Marky Dissod]

Might want to try to compare 6L80 '1500' TCC settings vs 6L90 '2500' settings?

 

[mikez71]

Comparing my 2012 Tahoe to a 2012 silverado 2500 6.0..
TCC regulator gain and offset the same.

TCC slip is a little different, stock 2012 Tahoe below

TCC slip for the 2500 is 20rpms for the entire map except the highest torque row which is set to 10rpms.

2018 silverado slip settings, similar to 2015 Tahoe settings.

Apply ramp is more aggressive in the low torque ranges, but less aggressive in the upper torque range.
stock 2012 Tahoe below

(2012 2500 6.0) pink cells are higher than stock, blue cells lower.

 

[j91z28d1]

interesting stuff.

 

[Marky Dissod]

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

 

[mikez71]

Just noticed 2010 Avalanche/tahoe/yukon/etc? apply ramps are more aggressive in same areas like the 2012 2500 apply ramps,
but without the lower values that the 2500 tune has! (Versus 2011+ tahoe/yukon/suburban tunes) The early tune looks more evenly gradiated.

more decimals, I should have expanded the others as well but didn't think they needed to calcute 1/4 rpms of targeted slip..