Silverado 6L80E Transmission Thermostat Delete

[Grumpy Bear]

42 minutes ago, newdude said:

Bringing up the dead here but it seems the OEMs and their maintenance charts are a bunch of phooey if you look at the ATF performance temp charts.  

 

GM front drives and now most of the rear drive applications have some sort of thermostat control on them.  It seems fluid suicide running them on the edge like that.  Perhaps GM needs to lower the opening temperature on them?  130-150F?  

The current crop of Group III/III+ fluid which are mineral oils will take more than the mineral oil shown in the chart which is a conventional Group II. Not as much as the PAO but 200 F is doable if you keep up on changing it often enough. The Group III's which were not available at the time this chart was put together in any large amount are fully saturated which hinders oxidation initiation temperature some. Problem has been that as the refining of these mineral oils has progressed the amount of oxidation inhibitors has been reduced and OEM operating temperatures have been increased consuming more thermal space than the chemistry has produced. Add to that the tow and haul wars the big three have going in the 1500 line ups and the fact that at least in the six speeds they have placed all the delicate electronics submerged in a hot oil bath......

 

From Machinery Lubrication: 

 

Identifying the Stages of Oil Oxidation

Bennett Fitch, Noria Corporation

Lubricants age and alter chemically by a process called oxidation. In fact, oxidation is the primary way a lubricant degrades over time from normal service. It typically results in impaired chemical and physical properties of the base oil and additives. Understanding why a lubricant oxidizes is essential to prevent, delay and monitor the process.

As oil is used in a machine over time, the oxidation process occurs, typically starting with the degradation of antioxidant additives. If the driving conditions that stress the oil remain unchanged, these additives will deplete at a near linear rate.

This is sometimes called the induction period. When the oxidation inhibitors are largely depleted, the breakpoint of the lubricant is reached, at which time the base oil has lost its first line of defense against oxidation.

Some base oils are extremely robust and resist oxidation naturally. Examples include most synthetics. However, if exposures to pro-oxidants such as high temperature, moisture, metal particles, agitation and oxygen are severe enough, even the most robust synthetics will give way to oxidize.

This oxidation process has the potential to begin almost spontaneously for even oil sitting dormant in a storage container. However, the rate of additive depletion and base oil oxidation generally correlates to the intensity of pro-oxidants existing within the oil.

Ultimately, the consequences of this chemical process will include increased oil viscosity and organic acids; the formation of sludge, varnish and deposits; additive depletion (including anti-wear additives, dispersants, corrosion inhibitors, etc.); and the loss of other vital base oil performance properties.

Once these undesirable lubricant conditions exist, the machine no longer will be protected effectively against friction, wear and corrosion.

 

Anyone who has followed Peppers build thread or has come to know me can witness to the fact I am likely a good representation of a person who operates his machines to the greatest possible enhancement for longevity/reliability. With that in mind I changed my AC-Delco Group III Dexron VI fluid first time at 50K miles and it was well on the way to being past it's sell date. Frankly....it was well past. Not burnt but well oxidized. Add depleted and no longer cherry red.   

 

I wonder...IF I had bought the 100K service life Kool-Aid GM is selling would I be sitting at 136,000 trouble free miles?  No way to know for sure I know, I know but................ 

[Grumpy Bear]

According to Ford Motor Company who shares technology with GM on the six speeds and under "Normal" operating conditions they see the fluid life as" 

 

Group I (1987) as 30,000 miles

Group II fluid life as 100,000 miles

Group III fluid life as 150,000 miles. 

 

Here's the fly in the ointment. "Normal" operating conditions for the most part do not exist thus ALL OEM's cut these numbers in half thus the 45,000 mile GM service intervals for 'Severe Service" Basically if you use your truck as a truck then your Group III super fluid is toast. As I attested to above. 

 

Secondly and what almost no one realizes is that it is the friction modifiers that give up first in an ATF that has had a lifetime of respectful maintenance and operation. 

 

Afton Chemical makes this note on their web site: 

 

Our OEM partners are enjoying the benefits of better fuel efficiency and more reliable transmissions. They are also experiencing reduced warranty problems and improved end-user satisfaction – including friction profiles lasting longer than 200,000 km.

 

That is 124,000 miles under ideal circumstances so it hardly matters the fluid under those same circumstances can go 150,000 miles before the oxidation additives and base oil give up.

 

Yes, this is true (friction modifier depletion) even of the PAO/Ester based oils which can take ridiculous amounts of heat. 

 

Thirdly, OEM transmission filters are notoriously loose. Not even good dog and cat catchers. More like Moose and Squirrel. Clutches generate particulates...lots of particulates. The only effective OEM method of removal is an fluid change. 

 

Anyway.....  OEM's could care less and the aftermarket is cherry picking to feature ONE thing that brand lubricant does really well as it it were all there was to fluids.  

 

 

 

Edited March 16, 2021 by Grumpy Bear

[swathdiver]

1 hour ago, Grumpy Bear said:

According to Ford Motor Company who shares technology with GM on the six speeds and under "Normal" operating conditions they see the fluid life as" 

 

Group I (1987) as 30,000 miles

Group II fluid life as 100,000 miles

Group III fluid life as 150,000 miles. 

 

Here's the fly in the ointment. "Normal" operating conditions for the most part do not exist thus ALL OEM's cut these numbers in half thus the 45,000 mile GM service intervals for 'Severe Service" Basically if you use your truck as a truck then your Group III super fluid is toast. As I attested to above. 

My experience exactly, Dex VI is dead by 45K or so and that is with minimal towing.

[Dick Lichon]

 

On 8/2/2020 at 12:41 PM, Grumpy Bear said:

I know personally two design engineers, (both now passed on) whose job it was to design the parts they were given to design to last 'just past' the warranty period. One from the now defunct Zenith  and the other from BMW. You remember Zenith who's slogan was, "The Quality goes in before the name goes on". 

 

True research in the manufacturing arena hasn't happened in decades. There is no interest in refinement for the sake of excellence  but there is a great interest in development for cash.  Companies don't make products. They make means to separate you from your cash. Bentley uses VW platforms to build profit margin in a mark that built it's reputation on excellence in design. The Buick LaCrosse and the Cadillac XTS are identical platforms and power trains. Different sheet metal and interior appointments separate two cars that are 20K + different in price. The Impala was the low margin fruit of that tree and was loped off. 

 

"New and Improved" today is marketing, not engineering and manufacturing. 

 

Now catch them in it! 

I used to design half shafts for GM many years ago. I remember designing a shaft that lived 180k miles on one of our prototype test runs. This was a severe duty cycle test. My boss told me to pull money out of it and make it live for 100k miles. Anyway, the above post is pretty spot on "in general" regarding products for the consumer market. The service side of the business is a large portion of revenue for auto makers. That is FACT.

[Rob Tucker]

I couldn't find an answer as to installing the sure cooler in a 6L80 voiding the manufacturer warranty. Does anyone know for sure? Thanks!

 

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

[70 W-30]

I flipped my thermostat this weekend on my 2015 with 60,000 miles. I thought I would be cute, and do it in place instead of taking it all the way out. Don't bother... It still only took about 20 minutes. I had been watching my temperature for the previous 3 weeks and the results are in. 185°F before, 147°F after the flip with the same outside air temperature, same roads. Well worth the effort.

[70 W-30]

Just a quick update... My fluid seems to be happy at 153°F during normal driving cycles in 90°F+ heat in Denver. Very happy with the results.

[Grumpy Bear]

3 hours ago, 70 W-30 said:

Just a quick update... My fluid seems to be happy at 153°F during normal driving cycles in 90°F+ heat in Denver. Very happy with the results.

 

Like your handle. Cute. 

Edited September 13, 2021 by Grumpy Bear

[scralatchtica824]

I just read through the thread this is a wealth of information. I'm going to go with the superior solutions insert on the 2018 5.3 3.42 1500 I just picked up with only 18,000 miles.