Silverado 6L80E Transmission Thermostat Delete

[Grumpy Bear]

2 hours ago, rav3 said:

@2kwik4u...Good input here. You sound like an engineer with good logic.

 

And you came to this conclusion how? 

5 hours ago, 2kwik4u said:

Weird......I don't either. Honestly, we're having an unarmed battle of data here. NEITHER OF US, knows exactly what it's supposed to do (as the engineers designed it, the programmers coded it, or the testers reported it) at any level of confidence. Unless we distill it so far as to say "make the truck move forward" we're picking the fly poop out of pepper. Because we simply do not know.

Was it this comment? He has no idea so yea, sounds like an engineer. 

 

Tell ya what. I've come to the conclusion that I listen poorly. Yea! It's true. 2kwick4u says he is happy with his as it is and it shifts like crap cold by his own testimony.

5 hours ago, 2kwik4u said:

My transmission DOES NOT work properly when it's cold. Shifts are firmer, and faster.

That last word is dead give away. OMG. 

 

So....honestly...why should I care what he thinks I do or don't know. 

 

I don't have this issue or ANY issue and I've been running bypassed for three winters, like automatics have for over a hundred years. 125K so far trouble free. This is the three years of data after the flip. You want a different result? Do it differently. Not my box.

 

 

 

 

 

 

 

[flyingfool]

17 hours ago, 2kwik4u said:

 

IMO, If you aren't overheating the transmission fluid (200deg +) for extended periods of time, there is ZERO benefit to cooling it any further, or messing with the system at any level. You are doing the modification for the sole purpose of making yourself feel better about the temp reading you're seeing. Excessive heat kills a transmission. Read that again. Excessive is the operative word there, and 192deg (88deg C) is not excessive. Combined with NOT changing shift parameters (such as clutch slip timing, shift timing, line pressures, etc) you are messing with a VERY well tested formula that we only have anecdotal evidence on.

 

 

anything over 165 is killing the durability IMO...

the evidence has been shown by many transmission rebuilders ...when you open up an old trans without cooling , you will see a hardenig of the soft rubber seals and o-rings, this causes pressure loss and clutch slip and bad shifts, flair issues, etc.also the TCM lives inside this hot oil bath,  and the delicate wafer films in the TECHM are made of a thin plastic , high temps are no good to this material ... my goal is to make it to 180,000 if not further before a taredown.  if you keep the t-stat i doubt you'll see 150,000 miles

 

after the delete and a KATEC 175engine t-stat  my trans operates at 135-145 city highway, towing is 165-75 degrees/

 

my next upgrade will be a Frantz by-pass filter..this will take care of particles down to .1 micron, 

Edited August 7, 2020 by flyingfool

[KARNUT]

anything over 165 is killing the durability IMO...
the evidence has been shown by many transmission rebuilders ...when you open up an old trans without cooling , you will see a hardenig of the soft rubber seals and o-rings, this causes pressure loss and clutch slip and bad shifts, flair issues, etc.also the TCM lives inside this hot oil bath,  and the delicate wafer films in the TECHM are made of a thin plastic , high temps are no good to this material ... my goal is to make it to 180,000 if not further before a taredown.  if you keep the t-stat i doubt you'll see 150,000 miles
 
after the delete and a KATEC 175engine t-stat  my trans operates at 135-145 city highway, towing is 165-75 degrees/
 
my next upgrade will be a Frantz by-pass filter..this will take care of particles down to .1 micron, 

I like to keep things simple. Back in the day we use to put on a cooler thermostat. If pulling a external transmission cooler. Now for fuel mileage and emissions hotter is better. Doesn’t the transmission fluid still go through the radiator and air-water cooling? Seems the water temperature would have to drop. Then emissions and fuel mileage suffers. With our pulling trucks we simply changed to synthetic (Amsoil) problem solved. This was starting with C-6 transmission up to the present day. The manufacturers have switch to synthetic. The transmission doesn’t have the problem with the heat, it’s the fluid. We found that with many different transmission over decades. With synthetic we never had a transmission failure again. Our combined loads were over 20Klbs, with our one tons.


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[newdude]

On 8/2/2020 at 9:14 AM, truckguy82 said:

I’ve read all your logic on this thermostat being worthless. And it does make sense, and it’s possible. But on the flip side, that would mean an entire team of engineers are complete morons. This thermostat is on one if the highest gross revenue vehicles in the world. Surely there was many calculations and people involved when deciding to add this thermostat.
 

My guess

-80% chance there is an advantage and we don’t know about it

-10% chance they are intentionally trying to reduce life of the transmission.
-10% chance they are all morons

 

Maybe we should get to the bottom of it and class action them if it was devious in nature. I would be pretty pissed if that was the case. I’d take a week off of work and dos attack whoever was responsible.

 

The 80%.  It was a fuel efficiency move all the way.  The quicker you get the fluid warmed, the quicker the viscosity of the fluid drops, the less drivetrain friction there is.  

 

2007-2013 6L80's never had a thermostat on them, and failure rate is much less than 2014-2018 at the dealer I work at.  

Edited August 7, 2020 by newdude

[flyingfool]

should be noted that many seals in a transmission like on the drum pistons are almost the equivalent of a windshield wiper.  you see how long those last 1 year maybe, 4-5 years on the new silicones ones sitting in the hot sun and weather 24/7

 

i agree synthetics are great , but dropping temps makes it even better. 

Edited August 7, 2020 by flyingfool

[newdude]

Some more food for thought.

 

6L80/90.  The Transmission Control Module (TCM) is internal to the transmission.  If you drop the pan, its an integral part of that solenoid control body that is directly above the filter.  That TCM sits in 190F fluid when the trans is up to temp.  Its largely a plastic body, with the solenoids, and a computer inside it. 

 

Computers and computer parts typically don't like heat.  Ever built a PC gaming/work station?  Temperature monitoring is a big key component, whether you are air or liquid cooled.  CPUs and GPUs don't like to get above certain working temperatures, say 90C for example.  They can start to throttle performance at or above those numbers, even shut down.

 

So that in mind, why do you think that GM would REMOVE the TCM from inside the transmission?  The 8L90, the Allison, the 10 speeds, all have External TCMs on them.  Away from the heat.  Away from soaking in 190F transmission fluid, so they can perform with CONSISTENCY.  

 

Also, I mentioned it in a reply above, but having worked in a GM dealer the last 10 years or so, you can keep track of the failure of things over time, and find out what makes things tick or makes them fail.  2007-2013 6L80s and 6L90s are not a common site to be seen sitting on a tech's bench torn apart.  There has been the occasional TCM changed, plenty of fluid changes, and a couple of removals for internal work.  

 

The K2 trucks  with 6L80s?  I've ordered torque converters, fluid pumps, TCMs, whole transmissions, lower carrier units, etc.  We've replaced 5 converters just this year so far.  The amount of teardowns surpasses the 07-13 trucks a good number here.  All of them had between 25k and 80k miles.  6L90s on the K2s do good still, but we've changed a few torque converters on those.  

 

So what gives?  The excessive heat from the addition of the thermostat is overworking the fluid, causing a faster degredation of the additive package?  Why did GM just release a flush procedure for the 6L80 to address fluid additive degredation?  The crappy designed torque converters that Sonnax ran a great article on showing the short comings of it?  That when they fail, destroy the fluid pump?  

 

Why do the HD trucks have less issues with no thermostat?  Why do the 07-13 trucks have less issues with no thermostat?  Why are some people in this thread running right away to discredit those with first hand experience on these transmissions and their performance and whether flipping the pill is good or bad?  Why do they jump to defend the engineers who's job is to just design and make it work at a price point/lifespan that appeases the OEM they work for?  I'm sure everyone more than noticed GM cut their powertrain warranty in 2016 down to 5 years/60,000 miles.  Why do you think they did that?  

Edited August 7, 2020 by newdude

[rav3]

41 minutes ago, newdude said:

Some more food for thought.

 

6L80/90.  The Transmission Control Module (TCM) is internal to the transmission.  If you drop the pan, its an integral part of that solenoid control body that is directly above the filter.  That TCM sits in 190F fluid when the trans is up to temp.  Its largely a plastic body, with the solenoids, and a computer inside it. 

 

Computers and computer parts typically don't like heat.  Ever built a PC gaming/work station?  Temperature monitoring is a big key component, whether you are air or liquid cooled.  CPUs and GPUs don't like to get above certain working temperatures, say 90C for example.  They can start to throttle performance at or above those numbers, even shut down.

 

So that in mind, why do you think that GM would REMOVE the TCM from inside the transmission?  The 8L90, the Allison, the 10 speeds, all have External TCMs on them.  Away from the heat.  Away from soaking in 190F transmission fluid, so they can perform with CONSISTENCY.  

 

Also, I mentioned it in a reply above, but having worked in a GM dealer the last 10 years or so, you can keep track of the failure of things over time, and find out what makes things tick or makes them fail.  2007-2013 6L80s and 6L90s are not a common site to be seen sitting on a tech's bench torn apart.  There has been the occasional TCM changed, plenty of fluid changes, and a couple of removals for internal work.  

 

The K2 trucks  with 6L80s?  I've ordered torque converters, fluid pumps, TCMs, whole transmissions, lower carrier units, etc.  We've replaced 5 converters just this year so far.  The amount of teardowns surpasses the 07-13 trucks a good number here.  All of them had between 25k and 80k miles.  6L90s on the K2s do good still, but we've changed a few torque converters on those.  

 

So what gives?  The excessive heat from the addition of the thermostat is overworking the fluid, causing a faster degredation of the additive package?  Why did GM just release a flush procedure for the 6L80 to address fluid additive degredation?  The crappy designed torque converters that Sonnax ran a great article on showing the short comings of it?  That when they fail, destroy the fluid pump?  

 

Why do the HD trucks have less issues with no thermostat?  Why do the 07-13 trucks have less issues with no thermostat?  Why are some people in this thread running right away to discredit those with first hand experience on these transmissions and their performance and whether flipping the pill is good or bad?  Why do they jump to defend the engineers who's job is to just design and make it work at a price point/lifespan that appeases the OEM they work for?  I'm sure everyone more than noticed GM cut their powertrain warranty in 2016 down to 5 years/60,000 miles.  Why do you think they did that?  

1st off, let me thank newdude for jumping in here with his great info. I'm glad to see input from someone that sees this stuff first hand & is willing to step up & report what he see's. Your info is what I've been looking for.

[Grumpy Bear]

2 X on kudos for newdude. Everyone learns when he speaks. Thanks!

[KARNUT]

Some more food for thought.

 

6L80/90.  The Transmission Control Module (TCM) is internal to the transmission.  If you drop the pan, its an integral part of that solenoid control body that is directly above the filter.  That TCM sits in 190F fluid when the trans is up to temp.  Its largely a plastic body, with the solenoids, and a computer inside it. 

 

Computers and computer parts typically don't like heat.  Ever built a PC gaming/work station?  Temperature monitoring is a big key component, whether you are air or liquid cooled.  CPUs and GPUs don't like to get above certain working temperatures, say 90C for example.  They can start to throttle performance at or above those numbers, even shut down.

 

So that in mind, why do you think that GM would REMOVE the TCM from inside the transmission?  The 8L90, the Allison, the 10 speeds, all have External TCMs on them.  Away from the heat.  Away from soaking in 190F transmission fluid, so they can perform with CONSISTENCY.  

 

Also, I mentioned it in a reply above, but having worked in a GM dealer the last 10 years or so, you can keep track of the failure of things over time, and find out what makes things tick or makes them fail.  2007-2013 6L80s and 6L90s are not a common site to be seen sitting on a tech's bench torn apart.  There has been the occasional TCM changed, plenty of fluid changes, and a couple of removals for internal work.  

 

The K2 trucks  with 6L80s?  I've ordered torque converters, fluid pumps, TCMs, whole transmissions, lower carrier units, etc.  We've replaced 5 converters just this year so far.  The amount of teardowns surpasses the 07-13 trucks a good number here.  All of them had between 25k and 80k miles.  6L90s on the K2s do good still, but we've changed a few torque converters on those.  

 

So what gives?  The excessive heat from the addition of the thermostat is overworking the fluid, causing a faster degredation of the additive package?  Why did GM just release a flush procedure for the 6L80 to address fluid additive degredation?  The crappy designed torque converters that Sonnax ran a great article on showing the short comings of it?  That when they fail, destroy the fluid pump?  

 

Why do the HD trucks have less issues with no thermostat?  Why do the 07-13 trucks have less issues with no thermostat?  Why are some people in this thread running right away to discredit those with first hand experience on these transmissions and their performance and whether flipping the pill is good or bad?  Why do they jump to defend the engineers who's job is to just design and make it work at a price point/lifespan that appeases the OEM they work for?  I'm sure everyone more than noticed GM cut their powertrain warranty in 2016 down to 5 years/60,000 miles.  Why do you think they did that?  

So GM wants to change their ads from the longest lasting to don’t let your warranty laps? The easiest it seems to me would be, one lose the thermostat or shorten the fluid changes. I can’t believe there’re that stupid. Well they did come up with cylinder deactivation, twice. Never mind.

 

 

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[newdude]

23 minutes ago, KARNUT said:

So GM wants to change their ads from the longest lasting to don’t let your warranty laps? The easiest it seems to me would be, one lose the thermostat or shorten the fluid changes. I can’t believe there’re that stupid. Well they did come up with cylinder deactivation, twice. Never mind.

 

 

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Not to derail from the topic, but AFM can be funny.  We have K2s that come in with well over 100K miles that have never had a lifter fail or burn oil.  We have a 2014 that hasn't had the trans out either.  But when you see a brand new 2020 with 2900 miles on it lose an AFM lifter?  The lowest bidder won somewhere....

[KARNUT]

 
Not to derail from the topic, but AFM can be funny.  We have K2s that come in with well over 100K miles that have never had a lifter fail or burn oil.  We have a 2014 that hasn't had the trans out either.  But when you see a brand new 2020 with 2900 miles on it lose an AFM lifter?  The lowest bidder won somewhere....

All for what maybe 2 miles per gallon. I put a tune in my 14 turned it off. No fuel mileage change. I guess if you chug around at 55 maybe. Who does that, old dude’s maybe.


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[Bob2C]

 
Not to derail from the topic, but AFM can be funny.  We have K2s that come in with well over 100K miles that have never had a lifter fail or burn oil.  We have a 2014 that hasn't had the trans out either.  But when you see a brand new 2020 with 2900 miles on it lose an AFM lifter?  The lowest bidder won somewhere....

Luck of the draw. Just like anything mass produced


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[Grumpy Bear]

5 hours ago, newdude said:

 

Not to derail from the topic, but AFM can be funny.  We have K2s that come in with well over 100K miles that have never had a lifter fail or burn oil.  We have a 2014 that hasn't had the trans out either.  But when you see a brand new 2020 with 2900 miles on it lose an AFM lifter?  The lowest bidder won somewhere....

I've seen lifters come out of motors that should have never been put in them. Non AFM lifter failures happen.  I've also seen really poor oil maintenance take the AFM out. Ridiculous abuse has killed some. I wish I knew the percentage of each type of failure. 

[truckguy82]

16 hours ago, Bob2C said:

Luck of the draw. Just like anything mass produced


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Yup

 

I’ve come to realize there is a wide range of quality in these trucks. Not sure if it’s because of sloppy tolerances or because they are built in different places.

 

I have to admit I wouldn’t expect the engine to be one of those places where you’re rolling the dice. Usually everything is precision machined.

[Bob2C]

Yup
 
I’ve come to realize there is a wide range of quality in these trucks. Not sure if it’s because of sloppy tolerances or because they are built in different places.
 
I have to admit I wouldn’t expect the engine to be one of those places where you’re rolling the dice. Usually everything is precision machined.

My fit and finish on my 18 Tahoe’s is not the best. I have owned others in the past and GM’s quality was always subpar in my opinion. The paint on my 18 is probably one of the worst I have seen. Didn’t notice until I spent the time detailing it. There are dust spots embedded throughout the whole car. I have never seen that in a factory paint job and I looked it over before I bought it but missed it. The one thing GM has over all other manufacturers is ride quality. Can’t be beat.


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