6L80E thermostat delete sure-cool cooler kit

Grumpy Bear · March 16, 2020

1 hour ago, truckguy82 said:

Whoa whoa whoa, you got up to 75mph!

Anyway thanks for the data.

Yeah that’s no too bad at all. I was more thinking like the northern states. In NJ the lowest we see is 0. I travel to VT a lot and we see probably -10 at the lowest. I was stationed in ND for a few years and we saw -25.

Should someone in ND remove the thermostat? Hell no. Should someone in VT remove their thermostat, no. Should someone in NJ remove their thermostat, eh maybe.

That was all I was trying to say.

As you know I live in northern Illinois and yes we saw -35 last year. No I wasn't out in it.

The fluid data was collected over the last 2 years. The previous 3 years the thermostat was being used. While I did not track transmission temperatures I have tracked fuel from day one. Every drop and every mile. For five years running the fuel efficiency has steadily improved. For five years my speed measured in miles / hours has also increased. For five years I have been lowering engine water temperature (graph). I lowered engine oil SAE viscosity grade

For the winters that the thermostat was being used the ATF temperature took about 100 miles of continuous highway driving @ 55 mph to reach the thermostat setting. It would take half that time to reach 110 F. Something it will do on the coldest days in 10 miles now. Why? The factory set up does not have a minimum flow bypass so the radiator can't act as a fluid heater as it does when the thermostat is removed.

Dexron D6 viscosity is the heavy end of a 5W motor oil cold. Once it is up to just 104 F (40c) it is about the same viscosity of 5W50 at 212 F. By 135 F it's already pretty light. The next 60 degrees only lowers the viscosity a few centipoise.

If your trip distance is say under 50 miles open road on a cold winter day your ATF temperature is actually higher with the thermostat removed than in play.

Lastly and as said before automatics have had radiator coolers for decades without a thermostat. I just showed with DATA that removing it does not hinder fuel efficiency. And it shift so sweet if you keep the fluid under 160F.

truckguy82 · March 16, 2020

18 minutes ago, Grumpy Bear said:

As you know I live in northern Illinois and yes we saw -35 last year. No I wasn't out in it.

The fluid data was collected over the last 2 years. The previous 3 years the thermostat was being used. While I did not track transmission temperatures I have tracked fuel from day one. Every drop and every mile. For five years running the fuel efficiency has steadily improved. For five years my speed measured in miles / hours has also increased. For five years I have been lowering engine water temperature (graph). I lowered engine oil SAE viscosity grade

For the winters that the thermostat was being used the ATF temperature took about 100 miles of continuous highway driving @ 55 mph to reach the thermostat setting. It would take half that time to reach 110 F. Something it will do on the coldest days in 10 miles now. Why? The factory set up does not have a minimum flow bypass so the radiator can't act as a fluid heater as it does when the thermostat is removed.

Dexron D6 viscosity is the heavy end of a 5W motor oil cold. Once it is up to just 104 F (40c) it is about the same viscosity of 5W50 at 212 F. By 135 F it's already pretty light. The next 60 degrees only lowers the viscosity a few centipoise.

If your trip distance is say under 50 miles open road on a cold winter day your ATF temperature is actually higher with the thermostat removed than in play.

Lastly and as said before automatics have had radiator coolers for decades without a thermostat. I just showed with DATA that removing it does not hinder fuel efficiency. And it shift so sweet if you keep the fluid under 160F.

so what’s your thought on why gm installed the trans thermostat?

Edited March 16, 2020 by truckguy82

Grumpy Bear · March 16, 2020

6 minutes ago, truckguy82 said:

I have literally raced my friend while towing multiple times. I have never seen high temps in my trans.

I once towed a 15k lb dump trailer, i saw 205. Which is only 5 degrees over where it’s supposed to be.

i tow frequently and have never had an overheating problem with the trans thermostat active

please show me any data that suggest running modern gm trans fluid at 190-200 degrees (where it is with the oem trans thermostat) degrades it’s life. This is the basis of your arguement.

i already know the answer, you can’t find it. There is zero data to prove that it’s bad for the fluid. You are just guessing. I know all about the trans temp debate.

The GM fluid is a PAO/Group III blend. The oxidation initiation temperature of the PAO is 200 F and the Group III below 190F. The temperature in the converter unlocked is about 80/100 F HIGHER than the bulk oil temperature. Warm enough with the thermostat in play to initiate oxidation of a POE whose trigger temperature is 250 F. The pan temperature is the supply temperature. The inner workings are hotter. Oxidation is unavoidable but the rate is controllable. With cooling and fluid choice.

Grumpy Bear · March 16, 2020

1 minute ago, truckguy82 said:

so what’s your thought on why the installed the trans thermostat?

Great question! ON PAPER it makes a difference. When they run test cycles engineers do what we call a 'cube'. They choose eight levers of influence and change one at a time to gauge the influence each lever has on the total result. There is always more than eight so the test are repeated with other choices in play and each set run a minimum of three times. It is tedious. Problem is if we have a 150 million drivers most of them will never duplicate the test sequence. It's an impossible ask for the engineer. So while the test show a plus the reality is quite different.

The powers the write the rules are forced then accept the physics. The physics says that reducing viscosity, even fractionally, is a reduction in energy required and thus an improvement in MPG. Few people ever get the EPA number, correct? There's some proof.

Then there is this. Bean counter have engineers whose sole purpose is to find the edge of the cliff. I've known several of these guys. One at BMW and one for Zenith. The warranty is 5 years. Design it to fail in five years and a week and get this guy to buy again. Dark I know but.... Even the relatively short period of time I spent in Research and Development I was tasked with this goal. Kid you not. One product team I was a member of was asked to do what physics/chemistry says can't be done. 50 million dollars later we had a product that looked like it worked well enough to fool the EPA. In practice the product, while meeting the EPA goals for VOC failed to meet performance standards required by customers. Who bough it anyway :crackup:

As a good friend of mine use to say, "Right idea, wrong method". Engineers, and I am one, are not gods and we have bosses.

I expect that if they would have included a minimum flow bypass and a temp trigger of about 160 F they wouldn't have the issues in reliability and drive-ability then have. It would have warmed up much quicker than it does and ran at a temperature that promoted long fluid life and ease of function. Anyway. that 's my thought on it.

Dmitri Mendeleev · March 16, 2020

12 minutes ago, Grumpy Bear said:

Great question! ON PAPER it makes a difference. When they run test cycles engineers do what we call a 'cube'. They choose eight levers of influence and change one at a time to gauge the influence each lever has on the total result. There is always more than eight so the test are repeated with other choices in play and each set run a minimum of three times. It is tedious. Problem is if we have a 150 million drivers most of them will never duplicate the test sequence. It's an impossible ask for the engineer. So while the test show a plus the reality is quite different.

The powers the write the rules are forced then accept the physics. The physics says that reducing viscosity, even fractionally, is a reduction in energy required and thus an improvement in MPG. Few people ever get the EPA number, correct? There's some proof.

Then there is this. Bean counter have engineers whose sole purpose is to find the edge of the cliff. I've known several of these guys. One at BMW and one for Zenith. The warranty is 5 years. Design it to fail in five years and a week and get this guy to buy again. Dark I know but.... Even the relatively short period of time I spent in Research and Development I was tasked with this goal. Kid you not. One product team I was a member of was asked to do what physics/chemistry says can't be done. 50 million dollars later we had a product that looked like it worked well enough to fool the EPA. In practice the product, while meeting the EPA goals for VOC failed to meet performance standards required by customers. Who bough it anyway

As a good friend of mine use to say, "Right idea, wrong method". Engineers, and I am one, are not gods and we have bosses.

I expect that if they would have included a minimum flow bypass and a temp trigger of about 160 F they wouldn't have the issues in reliability and drive-ability then have. It would have warmed up much quicker than it does and ran at a temperature that promoted long fluid life and ease of function. Anyway. that 's my thought on it.

I'm just going to leave these two links here as a proof of a general concept in industrial design today:

https://w__.youtube.com/watch?v=iiCBYAP_Sgg

https://w__.tundras.com/threads/2019-tundra-transmission-thermostat-location.42555/

Grumpy Bear · March 16, 2020

17 minutes ago, Dmitri Mendeleev said:

I'm just going to leave these two links here as a proof of a general concept in industrial design today:

https://w__.youtube.com/watch?v=iiCBYAP_Sgg

Point Set and Match

Epsilon Plus · August 8, 2020

On 3/9/2020 at 2:33 PM, Dmitri Mendeleev said:

These two explain the process of 'delete' or 'flip'.

For those that have done the flip like in the second video, is there enough room for the lines to hang down and do the flip process under the truck?

I'd rather not go to the trouble of disconnecting the entire line system.

Thanks.

Epsilon Plus · August 8, 2020

Answered my own question. It will drop down enough. I just undid the black plastic clips holding the lines (the ones attached to the bellhousing bracket). I also used a pair of Irwin quick grips to help compress the assembly as I put the snap ring back in. Some small C-Clamps would probably work good here too.

Dmitri Mendeleev · August 10, 2020

Good info;

I had my delete kit installed by the dealer.

Epsilon Plus · August 10, 2020

Good thread to check for more info, especially on my debacle haha.

jaimeastin · January 13, 2021

On 11/30/2019 at 4:20 PM, Jdezee said:

I was curious is anyone has used the below thermostat delete kit. I know it can be done with tapping the external block and plugging it but this looks like a cleaner install.

https://globaltransmissionparts.com/6l80-6l90-sure-cool-cooler-flow-system-stl010/?gclid=Cj0KCQiAw4jvBRCJARIsAHYewPPeHymu9JxSg2wnFVJhAmrMpteZhT3TLNEgu10Qz1dLDMP5qPkGJsQaAv59EALw_wcB

Looks like a cool kit but wanted to get some feedback if anyone has used it.

I just installed this. So far, my max temp is 145 degrees. I have not towed my boat yet.

I chose this kit as it is a true by pass. I decided to pay $42 rather than flip or tap. I could have done either. As everyone knows, but its very easy. When I towed my boat across country this past summer, my temps were in the 190s... I hope I will stay lower now. I and still thinking of adding a cooler.

Edited January 13, 2021 by jaimeastin

Yotaman · May 18, 2021

I finally got around too ordering and installing the kit. It was a easy and clean install. One of the things I worried about was if the Thermostat stuck closed and the Transmission overheated. I am lucky as I have no transmission trouble yet and have done two drain and fills and a new filter at 72K miles. I hope my trans last but just looking at youtube videos of them it is a miracle they function long at all they seem so complicated.

Anyway I appreciate the post and hope the lower temps help us all in the long run.

Yotaman

yourleftnut1 · May 21, 2021

So I'm a transmission builder for a major remanufacturing company. I'm quite new to this field. I rebuild 6L80/90, 4L60E, and 700. I owned a 2015 4.3L silverado. I'm new to GM trucks. I live in the midwest. The 190F transmission temps have always bothered me quit and bit. First I thought maybe an external cooler would be beneficial, but then after a ton of researches, it turns out, GM has the thermostat set at around 190F. This makes putting an external cooler useless.

I ran into this mod and this thread. Decided to give it a go, but using the TAP method. My normal temps dropped at least 20F. For city driving, I'm usually around 160F. Freeway at 75MPH, it's around 170F. Before even without a tow load, it would be around 195 in the summer. yikes! Like one user mentioned, during the winter, the temp never reaches 100F. That also bothers me too.. Hopefully this mod will help with that in the winter.

Anyways, I have torn down and put together 100's of 6L80/90's and I noticed that most of them have a burned smell and a lot of the time, the clutches, clutch plates, drums and shafts looked a bit toasted. lol. I wonder if that has anything to do with the temperature of the transmission. Not gonna lie, we get like 100's of 6L80/90's a week esp 6L80's. Almost made me regret buying my silverado.

yourleftnut1 · May 21, 2021

I love my silverado. 70k miles and no issues so far, but I must say, the transmission seems like the weakest link. I haven't messed with other auto manufacturer's transmission at work, but seems like GM took a short cut on the 4L60E's and 6L80/90's. Almost all the internals could be upgraded to a better part and it doesn't cost much more. Don't know what the previous owners used their trucks for, but we would get transmissions in with cracked drum pistons, cracked clutch plates, and many other things. We always replaced those failed parts using sonnax after market parts..

seems like the torque converter on my truck will eventually fail too. the good part is, I can rebuild my entire transmission in my garage and borrow tools from work to work on it over the weekend. i could even take it to work and have it test run on a dyno before installation.

Grumpy Bear · May 21, 2021

2 minutes ago, yourleftnut1 said:

seems like the torque converter on my truck will eventually fail too. the good part is, I can rebuild my entire transmission in my garage and borrow tools from work to work on it over the weekend. i could even take it to work and have it test run on a dyno before installation.

I believe the 4.3 converter uses a multi-plate captive clutch instead of the single plate. Feel free to correct me if you know otherwise. I won't mind a bit. Seem it's the JBMX behind the V8's that failure prone.

I too have the 4.3 now with about 140K on the clock. 100K with the pill flip, Red Line D6, PML 8 quart pan and 170 F water thermostat. It will reach the 104F minimum temperature in the dead of winter and do it faster than the OEM thermostat will permit. Those earlier temperature graphs are from my data. I do an 8 quart drop and fill every 25K. No smell and the fluid runs transparent. Not a hint of degradation. Shifts about as sweet as a slush box can.

You wouldn't happen to know the stall speed of this converter would you?