Trans temps

[CKNSLS]

Your right-"That Chart" is what it is. It's at least 20 year old chart that doesn't take in to account any synthetic or highly refined modern transmission fluids. OR-the improvements in transmissions themselves.

 

I tow all over the Intermountain West. Very high mountain passes.  When I had my 2011 Silverado-I drained the fluid at 50,000 miles. HALF of those miles were towing. HALF. Visually-the transmission fluid was a bright red.  Unfortunately ,I did not do a UOA. I regularly see temps of 235 on the steep ascents.

 

The DEX 6 is stout stuff. And really not a "True Synthetic " at least OEM wise-

ACDelco DEXRON-VI ATF is a high performance, synthetic blend formulation that meets or exceeds the stringent requirements of GM's DEXRON-VIspecification and provides warranty protection for current GM vehicles. 

 

 

Of course-full synthetic is available from many manufacturers.

Edited April 10, 2019 by CKNSLS

[Grumpy Bear]

From Circle D QA: 

 

TRANSMISSION MAINTENANCE

Q7. Why should I service my transmission and how often should I have it done?

Since heat is generated in an automatic transmission, the fluid will actually degrade and break down over time. By having your transmission serviced on a regular basis you will help extend the life of your transmission. Under normal driving conditions we suggest that you have your transmission serviced every 2 years or 25,000 miles. We also use a Universal Synthetic Transmission Fluid which aids in extending the life of your transmission by allowing it to run cooler and cleaner while lubricating your transmission and helping the fluid maintain its viscosity in a broad operating temperature range.

Even with THIER synthetic fluid they are recommending 2 year 25,000 mile changes. WHY? Heat degradation. 

Transmission Center: cut and paste

Why ATF (automatic transmission fluid) Wears Out

An automatic transmission creates a lot of internal heat through friction. The friction of the fluid churning inside the torque converter, the  friction created when the clutch plates engage, and the normal friction created by gears and bearings carrying their loads.

It doesn't take long for the automatic transmission fluid (ATF) to heat up once the vehicle is in motion. Normal driving will raise fluid temperatures to 80 degrees C., (176F) which is the usual temperature range at which most fluids are designed to operate. If fluid temperatures can be held to 80 degrees C., ATF will last almost indefinitely -- say up to 160,000 km (100,000 miles) But if the fluid temperature goes much higher, the life of the fluid begins to plummet. The problem is, even normal driving can push fluid temperatures well beyond safe limits, and once that happens, the trouble begins.

At elevated operating temperatures, ATF oxidizes, turns brown and takes on a smell like burnt toast. As heat destroys the fluid's lubricating qualities and friction characteristics, varnish begins to form on internal parts (such as the valve body),  which interferes with the operation of the transmission. If the temperature gets above 125 degrees C., rubber seals begin to harden, which leads to leaks and pressure losses. At higher temperatures the transmission begins to slip, which only aggravates overheating even more. Eventually the clutches burn out and the transmission calls it quits. The only way to repair the damage now is with an overhaul -- a job which can easily run upwards of $1500 on a late model front-wheel drive car or minivan.

As a rule of thumb, every 15 degree increase in operating temperature above 80 degrees C. cuts the life of the fluid in half!

At 90 degrees C., for instance, fluid life is reduced to 80,000 km. At 110 degrees, which is commonly encountered in many transmissions, the fluid is only good for about 60 000km. At 120 degrees C., the fluid won't go much over 15,000 km. Add another 20 degrees, and life expectancy drops to 8000kms. Go to 150 degrees C., and 1,000 to 1,500 klm is about all you'll get before the transmission burns up.

If you think this is propaganda put forth by the suppliers of ATF to sell more fluid, think again. According to the Automatic Transmission Rebuilders Association, 90% of ALL transmission failures are caused by overheating. And most of these can be blamed on worn out fluid that should have been replaced.

GM's own maintenance schedule is 45,000 miles With the thermostat. 

So yea, pour on the heat. 

Edited April 10, 2019 by Grumpy Bear

[wforrest08]

17 minutes ago, Grumpy Bear said:

This is just for fun: Something I ran across. Cut and Paste. 

 

Intermittent Harsh Downshift, Chuggle or Shudder During Deceleration 5.3L  Tahoe, Suburban, C/K Trucks Customer complaint may be harsh forced downshifts or the chuggle/shudder during a coast down intermittently. This is considered “Normal” with this powertrain package. It is a self test for the O2 sensors.  Test runs with the vehicle speed above 45 MPH (72 kph) in 6th gear with the TCC applied. The ECM drives the fuel system rich and then into deceleration fuel cutoff mode (shutting the injectors off) to check the system. Test will end during the deceleration and fuel is restored. (This typically causes the Shudder/Chuggle shift feel in the vehicle). Aggressive throttle response during this system check mode will cause the vehicle to have a “Harsh” downshift (this happens because the TCC remains applied during the test). If the test runs while in 5th gear, the TCC will not be applied and the complaint will not likely occur. Note: The test is designed to occur one time per key cycle, but can run up to 10 times if aborted due to throttle input.

Well that’s just dumb. Why wouldn’t there be a idiot light or a message on the DIC when in test mode? I mean my truck tells me all the most worthless info possible at the oddest times already, what’s one more right? Like ice may be possible when I pull out the garage and I am already 10 miles down the road cause it takes that long for the outside temp on the display to drop that low. Or my personal favorite when the OnStar chick out of the clear blue tells me this vehicle is connected to limited services...

[Grumpy Bear]

6 minutes ago, CKNSLS said:

Your right-"That Chart" is what it is. It's at least 20 year old chart that doesn't take in to account any synthetic or highly refined modern transmission fluids. OR-the improvements in transmissions themselves.

 

I tow all over the Intermountain West. Very high mountain passes.  When I had my 2011 Silverado-I drained the fluid at 50,000 miles. HALF of those miles were towing. HALF. Visually-the transmission fluid was a bright red.  Unfortunately ,I did not do a UOA. I regularly see temps of 235 on the steep ascents.

 

The DEX 6 is stout stuff. And really not a "True Synthetic " at least OEM wise-

ACDelco DEXRON-VI ATF is a high performance, synthetic blend formulation that meets or exceeds the stringent requirements of GM's DEXRON-VIspecification and provides warranty protection for current GM vehicles. 

 

 

Of course-full synthetic is available from many manufacturers.

Why? If you believe it will take anything you can throw at it why do you change it? Synthetic is an 'improvement' not a silver bullet. 

 

My first change at 50K, GM factory fill and thermostat in place. I don't tow. Fluid was well on it's way out. Remove stat and filled with Red Line D6 until I got a 90% plus turnover. 47,000 miles latter. Can't tell it's color from new. 

[Snowcamo]

Again, didn't say it wont take it. It isn't a matter of taking it once or twice or thirty dozen times. It's a matter of cumulative damage. That chart is what it is. Every major trans reman, stock or performance and cooler company still use it. B & M, TransGo, TCI. PAC, SONNAX, Circle D...…There is no magic. NASA didn't build this box.  
 
Not even GM evidently is comfortable with running a continuous 220F + or they wouldn't put a cooler on and even more cooler of the full Monty tow packages. Set alarms for temperature and limp modes. But hey, not being an engineer I'm sure you know better than the collective industry. You are right. My truck and it will never see those temperatures. Not even for a minute. 
 
Mobil makes claim for 500F for their Group III fluids. Not even a full on Polyol Ester Jet Turbine oil will take 500 F without some serious add pack heat enhancement. Your not going to find it in a $12 a quart fluid. 
 
What is true is ALL manufactures are under the gun for MPG numbers and waste reduction. Bring on the heat....The guts in this current 6L80E are evolving granted. 
 
For as much hate as the six speed gets for being a stumbling drunk I'm at a loss to explain why anyone, forum members, would do what they can to make it's life even shorter. 
 
This is just for fun: Something I ran across. Cut and Paste. 
 
Intermittent Harsh Downshift, Chuggle or Shudder During Deceleration 5.3L  Tahoe, Suburban, C/K Trucks Customer complaint may be harsh forced downshifts or the chuggle/shudder during a coast down intermittently. This is considered “Normal” with this powertrain package. It is a self test for the O2 sensors.  Test runs with the vehicle speed above 45 MPH (72 kph) in 6th gear with the TCC applied. The ECM drives the fuel system rich and then into deceleration fuel cutoff mode (shutting the injectors off) to check the system. Test will end during the deceleration and fuel is restored. (This typically causes the Shudder/Chuggle shift feel in the vehicle). Aggressive throttle response during this system check mode will cause the vehicle to have a “Harsh” downshift (this happens because the TCC remains applied during the test). If the test runs while in 5th gear, the TCC will not be applied and the complaint will not likely occur. Note: The test is designed to occur one time per key cycle, but can run up to 10 times if aborted due to throttle input.

Hey grumpy you rock!

[Grumpy Bear]

5 minutes ago, wforrest08 said:

Well that’s just dumb. Why wouldn’t there be a idiot light or a message on the DIC when in test mode? I mean my truck tells me all the most worthless info possible at the oddest times already, what’s one more right? Like ice may be possible when I pull out the garage and I am already 10 miles down the road cause it takes that long for the outside temp on the display to drop that low. Or my personal favorite when the OnStar chick out of the clear blue tells me this vehicle is connected to limited services...

Ron White can answer that for you...."Can't fix stupid" Now there is an example of engineers not doing the right thing, eh? There are no Elfin Magic guys. 

[CKNSLS]

5 minutes ago, Grumpy Bear said:

Why? If you believe it will take anything you can throw at it why do you change it? Synthetic is an 'improvement' not a silver bullet. 

 

My first change at 50K, GM factory fill and thermostat in place. I don't tow. Fluid was well on it's way out. Remove stat and filled with Red Line D6 until I got a 90% plus turnover. 47,000 miles latter. Can't tell it's color from new. 

Well-that's really curious when I'm towing (5,000 pounds) up 7,000 elevation mountain passes on a regular basis-and you don't do any towing and yours "was shot".

Edited April 10, 2019 by CKNSLS

[Grumpy Bear]

2 minutes ago, CKNSLS said:

Well-that's really curious when I'm towing (5,000 pounds) up 7,000 elevation mountain passes on a regular basis-and you don't do any towing and yours "was shot".

Can your read? Comprehend what you read? Did I say shot? 

[Timd32]

I have had a two Tahoe's since 07, now into a 19' Suburban....... thats why I joined this forum, glad to see the GM forum is as "heated" as the Ram forum I'm also on.

 

So I'll throw some oranges out there...

 

My daily driver is a 18' Dodge 2500 gas powered 6.4L with 6spd 66RFE, here is a comparison after towing a 9600lb trailer last week about 30miles thru some decent grades 10% in spots. Now ambient was 39deg but water and oil both in the 200's, Trans in the 170s. Its a stock work truck has the plow package better coolers and the sort made for work for sure. I keep an eye on my temps, that is my default display.  Heat kills transmission's plain amd simple, I am a trained SCIE going on about 19yrs started just after Y2K.

 

 

I'm sure just like Ram, the new displays show a made up number from some algorithms from various inputs, so alot of these reading we are looking at are not real..... but lets say they are real for now. 195 and into the 200s IMO is pretty hot for a "stock" trans, I would be figuring out a better cooler set up for my ride. Or make sure the temp is from a reliable location in the system.

 

 

 

[Jacoby]

I thought Grumpy was ruining this thread but nope a Ram owner had to come in and do it

[ksiesel]

I see a lot you guys quoting acutal trans temp numbers.  I have a Denali and from what I can find, the only way to see trans temp is in Tow/Haul mode and even then it’s just an analog gauge, not a digital readout.

 

Am I missing something, or is there a way to get a more precise trans temp number out of the Denali gauge cluster?

[Timd32]

39 minutes ago, Jacoby said:

I thought Grumpy was ruining this thread but nope a Ram owner had to come in and do it

Well I can't tow with this thing it's just a grocery getter.....

 

 

 

Have most of the fleet above.

 

11' Traverse heading up the driveway that has 140k on it .

Had

07' Tahoe Z71 139k

10' Tahoe LTZ 170k

 

So have a little Chevy seat time.

 

My daughter has her red Ford Raptor, there, so I'm a equal oppurtunity offender.

 

Cars are all about rebates, and financing anymore, who has the best deal month to month, Chevy did not have the #'s when I needed a 2500. Plus my local dealer has like no stock of work trucks ever, maybe 6 Corvette's, a few sub compacts, plain jane midsize, a few super high end pickups, and the rest is other brand preowned, its sad really.

 

Drove about 55min for my 19' Suburban to get the best deal, passed 2 other Chevy dealers. 

 

Getting back to the thread, heat really does kill transmissions, regardless of the name brand. 

 

 

 

[Jacoby]

1 hour ago, ksiesel said:

I see a lot you guys quoting acutal trans temp numbers.  I have a Denali and from what I can find, the only way to see trans temp is in Tow/Haul mode and even then it’s just an analog gauge, not a digital readout.

 

Am I missing something, or is there a way to get a more precise trans temp number out of the Denali gauge cluster?

Theyre probably using some 3rd party device to plug into the OBDII.  A lot of guys use their tuners.  I use a DashBoss that bluetooths the sensor info to my phone

47 minutes ago, Timd32 said:

Getting back to the thread, heat really does kill transmissions, regardless of the name brand. 

 

 

 

Heat yes but not 195-200* heat.  These transmissions can go 100k miles plus at that heat.  They've been doing it for decades

[Grumpy Bear]

10 hours ago, CKNSLS said:

I tow all over the Intermountain West. Very high mountain passes.  When I had my 2011 Silverado-I drained the fluid at 50,000 miles. HALF of those miles were towing. HALF. Visually-the transmission fluid was a bright red.  Unfortunately ,I did not do a UOA. I regularly see temps of 235 on the steep ascents.

I knew this guy.....actually, I still know him. Use to get off work and sit in the bar five nights a week and drink himself WELL past the walking limit then drive fifteen miles home. Never had so much as a close call. Would you say that is proof that drunk driving doesn't cause deaths? You couldn't convince this guy it was dangerous.

 

I'll never convince anyone who believes marketing over science that while PAO and POE's haver greater heat tolerance the parts they lubricate do not. These oils are more heat resistant but they are not heat proof. Something the aftermarket makes a living at, making parts that are more heat resistant, abele to take greater loads. Absorb more heat before delaminating clutch linings. Supplying more heat resistant seals and gaskets. 

 

Few seem to understand the difference between resistant and proof. If you are in a car that is taking fire do you want bullet resistant glass or bullet PROOF glass. Air is bullet resistant, you can prove it in court; but as soon as some marketer says greater resistance to heat the brain goes strait to ten foot tall and bullet proof. 

 

I've never said you can't get away with it and get away with it for quite some time. I'm not that guy that trades every three years and hands problems he's created off to grieve the next guy laughing at people for taking more than the usual care of things. I'm the guy who keeps a vehicle for two to five hundred thousand miles or until there is nothing to hang parts on. I take a very long view on maintenance and I've never burned a transmission up I kept under 175 F but I've fixed a few I bought burnt up.... Tell ya what else is true. No one that actually knows me ever blinks twice at buying my 200K plus equipment...if they can pry it from me. 

 

1 hour ago, Jacoby said:

I thought Grumpy was ruining this thread but nope a Ram owner had to come in and do it

That's funny. Odd point of view but funny. Dad use to say,  "Motor don't know what name is on the valve cover the oil is going into and neither does the oil".  Wendy's commercial use to say about chicken strips, "Parts is parts" 

[Grumpy Bear]

23 minutes ago, Jacoby said:

 

Heat yes but not 195-200* heat.  These transmissions can go 100k miles plus at that heat.  They've been doing it for decades

An actual true statement. But the chart isn't talking about transmission life. It's taking about transmission FLUID LIFE. 

 

Fluid running routinely at 203 F (95C) will last half as long as fluid at 176F (80C). Fluid at 230 F (110C) only last one quarter as long as fluid at 175 F. GM knows this. The severe service schedule states 45,000 mile changes. Their thermostat holds the fluid at.....right around  200 F or half that of holding it at...176F or lower. If GM who filled it with ExxonMobil (ACDelco) D6 and holds this view..…. Out fits like Circle D quoted earlier recommend changes at half GM's numbers using their full synthetics (box over 220F). 

 

As the fluid goes....so does the transmission. 

 

The OP can do as he chooses as can everyone else but in my boxes it stays under 175F and I run the best fluids I can get my hands on and change them like I don't pay attention to load, fluid or temperatures. See ya when I actually WEAR it out, not burn it out.  

 

The OP asked for an opinion, theirs mine.  It's okay if you don't like it.....

 

Edited April 10, 2019 by Grumpy Bear