Towing at the limit

[Grumpy Bear]

2 minutes ago, YukonXL04 said:

Is this an oil thread or a towing thread?

Isn't there already an oil thread where yall can go hash this out?

So you don't think the ATF is a concern in heavy towing. 

[ic3man5]

10 minutes ago, Grumpy Bear said:

That is  YOUR conclusion...not mine. I did not say that. Now take out the word I never said "MOST" and you've got it. 

 

Reading comprehension is not your long suit. In a water cooled motor the 'coolant' is pretty much constant once up to temperature AND when operated within the the design bounds of the system. Air cooled motors however operate with AIR as the coolant and oil temperature does follow air temperature for 'ANY GIVEN LOAD" and again within the limits of the systems ability to reject heat. I offered the example to show oil temperature is INFLUENCED by coolant temperature not that it is pegged to it. 

 

Now until YOU brought it up. 

Again this is YOUR conclusion, not mine. All I said was that temperatures are HIGHER in the bearings and that getting it above the melting point of the material used in bearing 'can' melt them. But it was offered more to show that pan temperatures are the average temperature and there are points in the motor where temperatures are higher. High enough to cause thermal breakdown. THEN offered that same sort of comparison in the transmission where converter temperatures are higher than pan temperatures WHEN the converter is operation unlocked and at maximum torque multiplication.

 

 

 

 

 

Now you are just pulling at strings without bringing anything to the conversation. Your examples aren't valid in proving your point; using a motorcycle with undersized heat dissipation relative to the engine is a horrible representation of what you are trying to prove out. Air/Oil cooled engine are not relative to this conversation by any means. Your previous example of correlating sludge to "bad" oils was also a very poor example as engine sludge is generally poor engine design or lack of maintenance.

 

So far you have brought up the following points that have no bearing or helpfulness to the OP (which probably already made a decision at this point):
-The base of the oil is super important (Its not)

-Oil is bad because it can sludge up and ruin an engine (Not correlated correctly).

-Air/Oil cooled engine is a great example of coolant to oil temp linear correlation (Its not).

 

I could go on more but this is getting boring and not interesting.

 

The fact that you can't even comprehend how much you stressed the "Importance" the base oil is laughable at best. Outside your knowledge of the type of base oil (which is creditable and vast) and being able to log thermal points on various points of the engine, your knowledge is very limited and not on topic or helpful here.

 

[asilverblazer]

On 4/8/2021 at 7:29 AM, ic3man5 said:

I can only assume this comment is indirectly directed towards me since I'm the only one that mentioned the divide by half rule; so here comes the information to fill in your ignorance:

 

Tow rating is determined by the following (J2807 Specification):

-0-30 mph in 12 seconds

-0-60 mph in 30 seconds

-40-60 mph in 18 seconds

-must be able to brake from 20 mph to zero in 45 feet with trailer brakes, or 80 feet without.

-needs to be able to maintain understeer as it accelerates on a circular skid pad from 0.1 g to 0.3 g of lateral acceleration.

-needs be able to tow its maximum trailer weight up a specific 11.4-mile uphill stretch of road in Arizona. For this test to be run correctly, it must be at least 100 degrees Fahrenheit outside, and the air conditioning must be on its maximum setting using outside air. The truck must maintain a minimum speed of 40 mph, and it can't throw any error codes or burn any fluids during the test. Grade of test is between 3-7% on the David Dam test.

 

None of this testing really covers real world testing with long distance or long duration travel. The most stressful test only lasts 15.2 minutes (11.4/45=0.2533). What makes this even worse is the Vehicle Warm-up is Optional or not specified in the test. 

 

So now that we have established a baseline we can see that tow limit specification doesn't specifically cover pushing the truck to its limits in all situations. Multiple people have already stated (including myself) the truck CAN NOT successfully tow extended distances at max tow rating without doing damage. Its already an established fact the TCC is weak in the K2 and is ran too hot to begin with. $300 tranny cooler vs $3000-5000 transmission rebuild because you decided to tow your daily driver a couple times a year at the limit; I know which one I'd pick. Sometimes it pays to be a worry wart and feel warm and fuzzy, but that is just me.

 

J2807 specification can be found here for further reading:

https://fifthwheelst.com/documents/tow-test-standards-2016-02.pdf

I wasn't particularly directing my comment to you. My facetious comments happened to align to your formula, regardless, I'll engage in a friendly debate with you anyways.

 

The J2807 test, which I am familiar with, is the industry accepted standard, and arguably is based on worst case scenarios. I'd further argue that J2807 is designed to approximate the infinite amount of variables in "real world testing with long distance or long duration travel". From the manufacturers point of view, there is no way they would build millions of these trucks rated at a certain weight without some degree of confidence that those vehicles will be able to accommodate that weight otherwise risking significant costs in warranty repairs.

 

You have unequivocally stated that the truck cannot tow its maximum rating extended distances without failure. I guess that is technically true, no vehicle can run forever without a failure. So I assume you have some data points in mind. What do you consider "extended distance"? 

 

You have also specifically claimed the TCC as the failure point. You used the term "multiple" to describe the quantity of failures of the TCC that are directly attributable to "extended distances at max tow rating." What data are you referencing? What percentage is that fail rate of the total trucks built? What percentage is that fail rate of trucks that tow at maximum rate 100% of the time? Also, specifically, that the failure of the TCC is a direct result of the towed weight for a specified distance that is defined as extended. 

 

I understand you forming an opinion that towing at half capacity may prolong the life of some component on your vehicle based on anecdotal evidence. By this reasoning, "the truck CAN NOT successfully" brake without wearing out the brake pads. Obviously, that doesn't make any sense. That's why ratings exist, so that we aren't applying arbitrary ratings that aren't backed up by facts and data. General Motors has access to failure rates of parts, operating conditions, costs, etc. that none of us have. Using that data along with specific tests such as the J2807 they have determined that the vehicle CAN successfully tow extended distances at max tow rating without doing damage. This is verified by their own publications: the owners manual has numerous guidelines about towing, none of them specify specific maximum distance at the already established maximum weight. Granted that "without damage" has to acknowledge that there is a failure rate of parts that will never be escaped. Again, these are machines that are not perfect, will encounter defects, flaws, assembly errors, etc. 

 

I'm not arguing that your TCC failure may have happened as a result of towing at the maximum weight for an extended period of time. But it cannot be guaranteed that it would not have happened at the 50% tow rating you have chosen either. 

 

To answer the original question, "would you feel comfortable towing in a setup like this with a weight distribution and sway control hitch or is this too much trailer for my half ton truck?" Is to provide an opinion of ones comfort level and a specific response to the trucks towing capacity, my response is yes and no, respectively. This is based on my comfort level derived from towing thousands of miles in varying conditions with several halt-ton trucks hitched to numerous trailers of varying type, length and weight. The second part of the question based on the data referenced above, General Motors published tow rating. 

[ic3man5]

21 minutes ago, asilverblazer said:

I wasn't particularly directing my comment to you. My facetious comments happened to align to your formula, regardless, I'll engage in a friendly debate with you anyways.

 

The J2807 test, which I am familiar with, is the industry accepted standard, and arguably is based on worst case scenarios. I'd further argue that J2807 is designed to approximate the infinite amount of variables in "real world testing with long distance or long duration travel". From the manufacturers point of view, there is no way they would build millions of these trucks rated at a certain weight without some degree of confidence that those vehicles will be able to accommodate that weight otherwise risking significant costs in warranty repairs.

 

You have unequivocally stated that the truck cannot tow its maximum rating extended distances without failure. I guess that is technically true, no vehicle can run forever without a failure. So I assume you have some data points in mind. What do you consider "extended distance"? 

 

You have also specifically claimed the TCC as the failure point. You used the term "multiple" to describe the quantity of failures of the TCC that are directly attributable to "extended distances at max tow rating." What data are you referencing? What percentage is that fail rate of the total trucks built? What percentage is that fail rate of trucks that tow at maximum rate 100% of the time? Also, specifically, that the failure of the TCC is a direct result of the towed weight for a specified distance that is defined as extended. 

 

I understand you forming an opinion that towing at half capacity may prolong the life of some component on your vehicle based on anecdotal evidence. By this reasoning, "the truck CAN NOT successfully" brake without wearing out the brake pads. Obviously, that doesn't make any sense. That's why ratings exist, so that we aren't applying arbitrary ratings that aren't backed up by facts and data. General Motors has access to failure rates of parts, operating conditions, costs, etc. that none of us have. Using that data along with specific tests such as the J2807 they have determined that the vehicle CAN successfully tow extended distances at max tow rating without doing damage. This is verified by their own publications: the owners manual has numerous guidelines about towing, none of them specify specific maximum distance at the already established maximum weight. Granted that "without damage" has to acknowledge that there is a failure rate of parts that will never be escaped. Again, these are machines that are not perfect, will encounter defects, flaws, assembly errors, etc. 

 

I'm not arguing that your TCC failure may have happened as a result of towing at the maximum weight for an extended period of time. But it cannot be guaranteed that it would not have happened at the 50% tow rating you have chosen either. 

 

To answer the original question, "would you feel comfortable towing in a setup like this with a weight distribution and sway control hitch or is this too much trailer for my half ton truck?" Is to provide an opinion of ones comfort level and a specific response to the trucks towing capacity, my response is yes and no, respectively. This is based on my comfort level derived from towing thousands of miles in varying conditions with several halt-ton trucks hitched to numerous trailers of varying type, length and weight. The second part of the question based on the data referenced above, General Motors published tow rating. 

I agree with everything you are saying; I jumped to conclusions assuming you were just repeating OEM specs without knowledge on the subject, sorry about that. Like you said we can't really know how bad the failure point is for the TCC; GM is the only ones that would know that and even that information is incomplete. Most of my knowledge on the TCC is from tuning and knowing how poorly its implemented on the software side; It seems to be a growing trend the TCC fails as early as 60K miles even without towing. I would categorize most of us on these forums as the 0.1 percenters that actually worry about stuff like this and most won't tow at the limit and if they do, not for very long. The tow rating IMO isn't a lie technically and it can do it but not without thermals increasing beyond safe limits and the J2807 test sadly doesn't test against. My Personal experience towing 7,000lbs @ 70MPH for about 3 hours was too much for it. The temperatures on the tranny were easily hitting 230/240F and the engine RPMS (L83 5.3L) were usually around 3-4.5K. I have to take a break half way through the trip to let it cool down a bit. This is with the TCC locked at all times and increased lock up pressure on the TC so I can only imagine how much more heat would be generated without the tuning and more slipping. Removing the thermostat did help increase how long I can tow before those temperatures are hit but it still happens. That being said I can tow 5,000k all day long and temperatures stay in check. Handling, braking, MPG, and engine torque all feel a lot better when the tow rating is cut in half IMO; This rule I only apply for 1500s and gas engines (Oh how I wish I had a 2500 and a diesel).

 

I also assume the OEMs will do just enough to cover reliability enough were it won't come back and be a PR nightmare and something attorneys can easily smash. Those of us that tow over 5,000lbs is far and in between so even if it does fail its not going to make much noise.

[Grumpy Bear]

2 hours ago, ic3man5 said:

Now you are just pulling at strings without bringing anything to the conversation. Your examples aren't valid in proving your point;

At this point I ask myself how I benefit from convincing you of anything what-so-ever. Know what that answer is? I don't. 

Next I ask myself if you learning something benefits me. Got the same answer. It doesn't. YOU are not trying to learn anything. Lastly I ask myself if I'm ready to cancel 40 years in the oil/gas/chemical business and my education start doubting my life.

 

What to guess what that answer might be? 

 

Is it even possible to have a conversation with someone to whom facts are not what they are but only what THEY say they are.

I say gravity has an acceleration rate of.....and before it is out of my mouth you're telling gravity is old, invalid and not real!!

 

Sorry, I have this caricature flaw; I have issues with the irrational and unreasonable. 

 

So....not a battle I need to win. Not a battle I need to fight.

 

 

[Grumpy Bear]

On 3/19/2021 at 9:38 PM, nominion said:

Tow Vehicle Info

 

2018 GMC Sierra 1500 SLT Crew Cab Short Box

5.3L Engine

8L90 Transmission

Trailering package

3.42 Gearing

 

GVWR:    7200 lbs
GCWR:    15000 lbs
Towing Capacity:    9100 lbs
Curb Weight:    5695 lbs
Passenger Weight:    300 lbs (2 people)
Cargo Weight:    225 lbs (26 gallons of fuel, hitch, misc. stuff)
Estimated Vehicle Weight:    7198 lbs

 

Travel Trailer Info

GVWR:    9584 lbs
Dry Weight:    6826 lbs
Cargo Weight:    1000 lbs (estimate of food/beverages, water, clothing, misc. camping gear)
Estimated Hitch Weight:    978 lbs
Estimated Trailer Weight:    7826 lbs

 

I know the total trailer weight, current vehicle weight, and combined weight are at the limit.  Cargo weights are estimated, so there is some room to adjust. 

 

I'm considering a new travel trailer and I'm on the fence about my current half ton truck.  We are a family of 6, so the travel trailer needs to be big to accommodate all of us.  Regardless of the tow vehicle, a second vehicle will be involved just to carry everyone.

 

Would you feel comfortable towing in a setup like this with a weight distribution and sway control hitch or is this too much trailer for my half ton truck?

 

 

No

 

I trust that is "On Point" direct enough.

[asilverblazer]

22 hours ago, ic3man5 said:

I agree with everything you are saying; I jumped to conclusions assuming you were just repeating OEM specs without knowledge on the subject, sorry about that. Like you said we can't really know how bad the failure point is for the TCC; GM is the only ones that would know that and even that information is incomplete. Most of my knowledge on the TCC is from tuning and knowing how poorly its implemented on the software side; It seems to be a growing trend the TCC fails as early as 60K miles even without towing. I would categorize most of us on these forums as the 0.1 percenters that actually worry about stuff like this and most won't tow at the limit and if they do, not for very long. The tow rating IMO isn't a lie technically and it can do it but not without thermals increasing beyond safe limits and the J2807 test sadly doesn't test against. My Personal experience towing 7,000lbs @ 70MPH for about 3 hours was too much for it. The temperatures on the tranny were easily hitting 230/240F and the engine RPMS (L83 5.3L) were usually around 3-4.5K. I have to take a break half way through the trip to let it cool down a bit. This is with the TCC locked at all times and increased lock up pressure on the TC so I can only imagine how much more heat would be generated without the tuning and more slipping. Removing the thermostat did help increase how long I can tow before those temperatures are hit but it still happens. That being said I can tow 5,000k all day long and temperatures stay in check. Handling, braking, MPG, and engine torque all feel a lot better when the tow rating is cut in half IMO; This rule I only apply for 1500s and gas engines (Oh how I wish I had a 2500 and a diesel).

 

I also assume the OEMs will do just enough to cover reliability enough were it won't come back and be a PR nightmare and something attorneys can easily smash. Those of us that tow over 5,000lbs is far and in between so even if it does fail its not going to make much noise.

I appreciate the additional discussion points, "The tow rating IMO isn't a lie technically and it can do it but not without thermals increasing beyond safe limits and the J2807 test sadly doesn't test against. My Personal experience towing 7,000lbs @ 70MPH for about 3 hours was too much for it. The temperatures on the tranny were easily hitting 230/240F" "That being said I can tow 5,000k all day long and temperatures stay in check."

 

What was the terrain and ambient temperature like? I ask because the J2807 is supposed to be done at fairly high ambient temperature on a steep grade.

 

Going out on a limb here to expect this but but here goes... Presumably, GM would monitor the fluid temperatures during the J2807 testing for at least their own knowledge, I would expect the transmission temperature to easily reach the temperature you report during the test. If so, I guess this discussion quickly becomes what is a safe temperature for the fluid to reach before what? Are they expecting cool down periods when coasting down the other side of the hill. It's not hard to imagine a scenario out there where the TCC is open longer than the test, and it's potentially hotter than J2807 requires, did GM put in a margin to account for it, or are the scenarios and probabilities becoming so rare or unlikely that they decided the risk isn't that great.

 

"I also assume the OEMs will do just enough to cover reliability enough were it won't come back and be a PR nightmare and something attorneys can easily smash. Those of us that tow over 5,000lbs is far and in between so even if it does fail its not going to make much noise." I don't want to agree but I think its the sad reality, that a cost/benefit/risk was conducted... 

 

Leading to "common sense" when operating the vehicle regardless of what you are towing, over what terrain, at what temperatures, is to monitor the vehicle and take remedial action if something is amiss. To your point, the chances of that happening "when the tow rating is cut in half" are much lower. I would say that if I am towing maximum weight and encounter an increased transmission fluid temperature and decide to slow down, pull over, etc. that isn't necessarily a failure or inability to to do it, in the same way that if I experience swaying, I would slow down or increased braking distances I would brake sooner.

 

So that I understand your position better when you say "when the tow rating is cut in half" you are basing that off your experience "tow 5,000k all day long and temperatures stay in check;" this gives me the impression this weight is at a point where you are comfortable not needing to monitor the transmission temperature (which I would also agree with). You then mention a 2500 diesel, would you cut its tow rating in half or determine an amount that you can operate the vehicle at all day with out concern for monitoring the transmission temperature?

 

Also something neither of us are particularly discussing but should not be ignored is the type of trailer. A 10000lb steel ingot on a lowboy utility trailer is a vastly different towing experience than a 5000lb travel trailer. The OP is talking about a travel trailer and based on that wind drag plays a significant role, cross winds and head winds should not be ignored (goes back to above, it may require a lower speed...)

 

 

 

[Grumpy Bear]

10 hours ago, asilverblazer said:

Going out on a limb here to expect this but but here goes... Presumably, GM would monitor the fluid temperatures during the J2807 testing for at least their own knowledge, I would expect the transmission temperature to easily reach the temperature you report during the test. If so, I guess this discussion quickly becomes what is a safe temperature for the fluid to reach before what? Are they expecting cool down periods when coasting down the other side of the hill. It's not hard to imagine a scenario out there where the TCC is open longer than the test, and it's potentially hotter than J2807 requires, did GM put in a margin to account for it, or are the scenarios and probabilities becoming so rare or unlikely that they decided the risk isn't that great.

Forget for a moment how much heat the fluid can take or which fluid is best. Concentrate on how much the components can take and remember that the pan is the coolest fluid in the the transmission and the the components are by shear reason hotter or they wouldn't heat the fluid requiring a cooler. When this chart says Seals Harden at 240 F a guy has to use his head. You cook a roast at 225 F or it can be done at 375 F...and the difference is? TIME. Anyone that thinks GM Engineers have it all together can explain this to me....In the 6L80E the TCM is located in????? A bath of hot oil. There's a genius move. 

 

Mobil 1 gets away with the obvious lie that their ATF can take 500F by?????? No reference to time. Ever watch your mother as a child touch her finger tips to a iron to see if it was hot enough for cotton? How long did she hold them there. What would be the consequence of say 20 minutes of contact? Time is the difference between it feels warm and total destruction. 

 

Get a large cooler with a fan. Large enough to keep that pan temperature at least under 180 F. 

 

TCC is not locked up when you're 4,000 rpm in 4th gear. Converter temperatures are higher. Not as high as launch at maximum slip but still quite a bit higher. 

 

                                            

 

 

Edited April 15, 2021 by Grumpy Bear

[ic3man5]

9 hours ago, asilverblazer said:

I appreciate the additional discussion points, "The tow rating IMO isn't a lie technically and it can do it but not without thermals increasing beyond safe limits and the J2807 test sadly doesn't test against. My Personal experience towing 7,000lbs @ 70MPH for about 3 hours was too much for it. The temperatures on the tranny were easily hitting 230/240F" "That being said I can tow 5,000k all day long and temperatures stay in check."

 

What was the terrain and ambient temperature like? I ask because the J2807 is supposed to be done at fairly high ambient temperature on a steep grade.

Roughly about 80-85F and little to no slope (last 20 miles might be a like a 1-3 degree incline. So I'm under the test requirements for the J2807 test but I'm moving faster so its probably similar energy outputs but no way to measure it.

9 hours ago, asilverblazer said:

Going out on a limb here to expect this but but here goes... Presumably, GM would monitor the fluid temperatures during the J2807 testing for at least their own knowledge, I would expect the transmission temperature to easily reach the temperature you report during the test. If so, I guess this discussion quickly becomes what is a safe temperature for the fluid to reach before what? Are they expecting cool down periods when coasting down the other side of the hill. It's not hard to imagine a scenario out there where the TCC is open longer than the test, and it's potentially hotter than J2807 requires, did GM put in a margin to account for it, or are the scenarios and probabilities becoming so rare or unlikely that they decided the risk isn't that great.

The thing that sucks about the J2807 test is the requirements don't say anything about temperatures but it simply can't burn any fluids, which won't happen until the oil is hitting 400F+ (For a decent oil anyways, cheap oils can be close to 300F). The torque converter lock up is very aggressive in the 6L80 so that should decrease heat but the TCC is always slipping 40-100 RPM in a stock tune. I agree their risk assessment was in the benefit for a "smoother" ride over longevity.

9 hours ago, asilverblazer said:

"I also assume the OEMs will do just enough to cover reliability enough were it won't come back and be a PR nightmare and something attorneys can easily smash. Those of us that tow over 5,000lbs is far and in between so even if it does fail its not going to make much noise." I don't want to agree but I think its the sad reality, that a cost/benefit/risk was conducted... 

 

Leading to "common sense" when operating the vehicle regardless of what you are towing, over what terrain, at what temperatures, is to monitor the vehicle and take remedial action if something is amiss. To your point, the chances of that happening "when the tow rating is cut in half" are much lower. I would say that if I am towing maximum weight and encounter an increased transmission fluid temperature and decide to slow down, pull over, etc. that isn't necessarily a failure or inability to to do it, in the same way that if I experience swaying, I would slow down or increased braking distances I would brake sooner.

 

So that I understand your position better when you say "when the tow rating is cut in half" you are basing that off your experience "tow 5,000k all day long and temperatures stay in check;" this gives me the impression this weight is at a point where you are comfortable not needing to monitor the transmission temperature (which I would also agree with). You then mention a 2500 diesel, would you cut its tow rating in half or determine an amount that you can operate the vehicle at all day with out concern for monitoring the transmission temperature?

Yes I feel completely comfortable with that AND it gives the benefit of not stopping. Sometimes the time allowance simply isn't there to allow for stops or you have passengers that are hard to manage (kids / wife) and every stop means either spending more money or possibly increased crabbiness, etc. As for the diesel, I would feel more comfortable towing near the limit (Lets say 3/4 instead of 1/2) but I'd still monitor it and probably still add a transmission cooler.

9 hours ago, asilverblazer said:

Also something neither of us are particularly discussing but should not be ignored is the type of trailer. A 10000lb steel ingot on a lowboy utility trailer is a vastly different towing experience than a 5000lb travel trailer. The OP is talking about a travel trailer and based on that wind drag plays a significant role, cross winds and head winds should not be ignored (goes back to above, it may require a lower speed...)

 

 

 

I was going to factor in wind resistance also but its already such a huge topic I left it out; My experience is worse case 24ft long 7/8ft tall and requires tow mirrors. 

[ic3man5]

9 hours ago, Grumpy Bear said:

Anyone that thinks GM Engineers have it all together can explain this to me....In the 6L80E the TCM is located in????? A bath of hot oil. There's a genius move. 

The TCM can at a bare minimum withstand 257F constantly and it won't fry the second it goes over that. It should be able to withstand way higher but I don't have access to that information without tearing apart a T43 Module.

Quote

 

TCC is not locked up when you're 4,000 rpm in 4th gear. Converter temperatures are higher. Not as high as launch at maximum slip but still quite a bit higher. 

TCC is never unlocked in the 6L80 under heavy torque load (184ft lb+) (Not accounting for bugs in the software). If you are referring to the torque converter itself its very rarely unlocked unless at WOT and near the end of the shift. See below for the shift tables:

 

Edited April 15, 2021 by ic3man5

[Grumpy Bear]

10 hours ago, asilverblazer said:

Going out on a limb here to expect this but but here goes... Presumably, GM would monitor the fluid temperatures during the J2807 testing for at least their own knowledge, I would expect the transmission temperature to easily reach the temperature you report during the test. If so, I guess this discussion quickly becomes what is a safe temperature for the fluid to reach before what? Are they expecting cool down periods when coasting down the other side of the hill. It's not hard to imagine a scenario out there where the TCC is open longer than the test, and it's potentially hotter than J2807 requires, did GM put in a margin to account for it, or are the scenarios and probabilities becoming so rare or unlikely that they decided the risk isn't that great.

Source (Machinery Lubrication)

 

Source (Chevron/Phillips)

Having a high viscosity index helps to protect an engine at temperature extremes. However, VI doesn’t tell the whole story — it only reflects the viscosity/temperature relationship between 40°C and 100°C. But what happens below 40°C?

 

High temperatures can thin and break down oil, crippling its lubricating ability, whereas low temperatures can rob a lubricant of its ability to reach critical parts. Two lubricants with the same VI may perform dramatically differently at low temperatures. Note the differences between a VHVI mineral oil and Synfluid^® Polyalphaolefin (PAO) 5 in the Scanning Brookfield chart below.

Oils made with PAOs demonstrate an inherently high viscosity index and maintain excellent low-temperature performance, compared with mineral oils. While viscosity improvers can enhance VI, they can break down over time, resulting in diminished performance. The reason a PAO is selected as a lubricant basestock is its ability to improve performance and solve problems.

 

Today’s lubricants demand better oxidative stability. What advantages do Synfluid® PAOs have?

Oxidative stability is a critical property enabling oils to resist sludge formation and degradation while in service. PAO-based lubricants offer a significant advantage in oxidative stability. The rotary bomb bench test is a strong predictor of how base oils will perform in many automotive and industrial applications. The chart below shows rotary bomb (ASTM D2272) results between Synfluid^® PAOs and some mineral oils.

Synfluid^® PAOs have been carefully designed to yield oxidative induction times greater than 2,500 minutes with 0.5 percent antioxidant. This is a far greater benefit than can be achieved from other base oils.

 

PAOs also resist viscosity increases upon oxidation, which is important in sequence IIIE and VW T4 engine tests. These combined benefits provide the properties required for severe service applications and extended drain intervals.

The advantages offered in oxidative stability, coupled with superior volatility and low-temperature viscometrics, clearly demonstrate that Synfluid^® PAOs are the highest-quality base oils available in the industry.

 

Use it, ignore it, whatever..... You can refine a mineral oil until pigs fly and it will not EVER compete with a PAO/POE oil.

 

One of my favorites: Same results in my transmission. PAO/POE run cooler. Why? Higher thermal capacity. 

 

Source (Pepper, my personal truck)

 

I’ve heard that PAOs can reduce the operating temperature of equipment. How does this work?

That’s a hot topic! There are several systems where we have observed a reduction in the operating temperature compared to mineral oils, including transmissions, engines and heat transfer applications. Why does this happen? We believe it can be understood by looking at the thermal conductivity and specific heat of the base oils.

Thermal conductivity is the measure of the ability to conduct heat. Specific heat is the amount of heat per unit mass required to raise the temperature one degree Celsius. The chart below shows that the PAO has a higher specific heat, which means that the PAO is better at absorbing heat. Furthermore, thermal conductivity at 300°F for PAO 6 is 0.085 compared to 0.071 Btu•ft/(h•ft2•°F) for an equiviscous mineral oil, which means that the PAO can conduct 20 percent more heat than the mineral oil for better heat dissipation.

Chemical kinetics tell us that if you reduce the temperature, you will reduce the reaction rate. Oxidative and other lubricant degradation mechanisms would follow the same trend. Therefore, reducing the temperature is generally beneficial in extending the life of a lubricant.

 

                                                   Like I said. I don't guess. I measure and report. 

 

                                          In no world is it okay to submerge electronics in hot oil.

There's a reason your computer has a fan and isn't in a tank of oil. GM does NOT have any special little green men from mars building  super computers from unobtainium.  

 

Edited April 15, 2021 by Grumpy Bear

[ic3man5]

12 hours ago, Grumpy Bear said:

 

                                                   Like I said. I don't guess. I measure and report. 

 

                                          In no world is it okay to submerge electronics in hot oil.

There's a reason your computer has a fan and isn't in a tank of oil. GM does NOT have any special little green men from mars building  super computers from unobtainium.  

 

Its clear you don't have an understanding on how electronics work, stop guessing here. Majority of electronics in this world don't require fans for thermal dissipation. Everything you stated here is just plain false. 

[asilverblazer]

On 4/14/2021 at 1:13 PM, Grumpy Bear said:

Forget for a moment how much heat the fluid can take or which fluid is best. Concentrate on how much the components can take and remember that the pan is the coolest fluid in the the transmission and the the components are by shear reason hotter or they wouldn't heat the fluid requiring a cooler. When this chart says Seals Harden at 240 F a guy has to use his head. You cook a roast at 225 F or it can be done at 375 F...and the difference is? TIME.

 

                                            

 

 

Simplest explanation so far regarding what the result of subjecting the components to a certain temperature over a period of time. 

 

Highlights the importance of understanding what temperatures you might be subjecting the components to based on what you are doing. If you are towing at the maximum weights, or otherwise subjecting the vehicle to a high load (via grade, weight, aerodynamic drag, temperature, etc.) it may require adapting the driving for those conditions.

[asilverblazer]

15 hours ago, ic3man5 said:

Roughly about 80-85F and little to no slope (last 20 miles might be a like a 1-3 degree incline. So I'm under the test requirements for the J2807 test but I'm moving faster so its probably similar energy outputs but no way to measure it.

The thing that sucks about the J2807 test is the requirements don't say anything about temperatures but it simply can't burn any fluids, which won't happen until the oil is hitting 400F+ (For a decent oil anyways, cheap oils can be close to 300F). The torque converter lock up is very aggressive in the 6L80 so that should decrease heat but the TCC is always slipping 40-100 RPM in a stock tune. I agree their risk assessment was in the benefit for a "smoother" ride over longevity.

Yes I feel completely comfortable with that AND it gives the benefit of not stopping. Sometimes the time allowance simply isn't there to allow for stops or you have passengers that are hard to manage (kids / wife) and every stop means either spending more money or possibly increased crabbiness, etc. As for the diesel, I would feel more comfortable towing near the limit (Lets say 3/4 instead of 1/2) but I'd still monitor it and probably still add a transmission cooler.

I was going to factor in wind resistance also but its already such a huge topic I left it out; My experience is worse case 24ft long 7/8ft tall and requires tow mirrors. 

Thanks for your thoughts and the excellent discussion.

[Grumpy Bear]

5 hours ago, asilverblazer said:

Simplest explanation so far regarding what the result of subjecting the components to a certain temperature over a period of time. 

 

Highlights the importance of understanding what temperatures you might be subjecting the components to based on what you are doing. If you are towing at the maximum weights, or otherwise subjecting the vehicle to a high load (via grade, weight, aerodynamic drag, temperature, etc.) it may require adapting the driving for those conditions.

Never under estimate the usefulness of an additional transmission cooler.

 

Grownups are like children on one regard. They like to see how close to the edge they can stand.