Jump to content

Transmission Temp

Recommended Posts

17 minutes ago, shakenfake said:

Yes hills will make a difference. 205 isn't that bad but I would invest in a trucool 40k transmission coolers to help lower them a little bit more. Your transmission will thank you for it

Thank you, I really appreciate the assistance. 

Link to comment
Share on other sites

On 10/8/2021 at 4:28 PM, CamGTP said:

There really isn't a problem until you are well past 225-230 degrees and climbing.


A larger cooler will help bring the temps down.

Thank you. I’m buying an after market transmission cooler. Just have to find a place to install it. Again thank you. 

Link to comment
Share on other sites

23 hours ago, Black02Silverado said:

Also, if you have not done it, I would change out the transmission fluid.  Keeping it fresh every 30k to 40k miles is a major benefit.

I just did about a few months ago. It stayed pretty consistent. Didn’t notice a drop but it also doesn’t get hotter. 205 is the hottest it’s gotten. Thank you though. I will definitely keep up with fluid changes. 

  • Like 1
Link to comment
Share on other sites

I've put up the trans life chart dozens of times and it gets ignored and forgotten. I see TCI is now saying the box works best between 175 F and 225 F an now everyone is echoing that range.


WORKS BEST is not the same as LAST LONGEST



I have no idea what TCI means by "WORKS BEST".  Before my cooler modifications my fluid ran between 220 F and 240 F and GM told me it was 'normal'. After some cooler work I now run 110 F (winter) to 175 F (summer). IMHO it shifts better cooler. Just like they always do. IN addition the factory GM OEM fill fluid was done by 45K. So much for Group III Synthetic being 'just as good' as PAO/POE fluids.  




In this post (link above) we get more detail that the broad generalization of TCI: 


[quote] 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 175 degrees F., which is the usual temperature range at which most fluids are designed to operate. If fluid temperatures can be held to 175 degrees F., ATF will last almost indefinitely -- say up to 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. [end quote]


This information generates the FLUID life chart (below) and we circle back to the 50 year old 180 F limit ALL transmission builders have used as a guide. Funny how that works once the EPA and OEM gets out of the way.  


It isn't that you can't run hotter and be more efficient. It's that you can't do both. That is long transmission life AND maximum fuel economy. Pick your poison.  








Edited by Grumpy Bear
  • Like 2
Link to comment
Share on other sites

Transmission life is reliant on the fluid used. I’ve towed for 40 years mostly with automatic transmissions the last 20. Once I switch to synthetic, Amsoil mostly we started getting past 100K on transmission life. Logically changing more often depending on pulling rate is a given. The manual with your vehicle has recommended limits and maintenance guidance depending on usages. I’d be a little suspect of flipping pills and running too cool in the transmission. I’d add a cooler before doing that. The way everything is tied together for efficiency I’d be suspect. I remember back in 98 with my Ford power stroke automatic. Until it reached a certain temperature it held back power. I can imagine running too cool temperatures could still have the same results. 

  • Like 2
Link to comment
Share on other sites

2 hours ago, elcamino said:

There's better made ATF lubricants on today's market that meet and exceed OEM (requirements)  and do a much better job.


Better at what and which ones? Rhetorical question. Let's ask a question. What is the purpose of hydrocracking and hydrotreating? That thing that turns a Group II into a Group III "Synthetic"!


To REFORM the molecules from aromatics and unsaturated structures to shorter fully saturated straight and branch chained molecules. 




And what does this do? It makes it harder to thermally and chemically decompose. Slooooows oxidation. BUT it does not prevent it. Antioxidants are still required and those chemicals are the same as those used in Group II fluids and are HEAT SENSITIVE. They (the additives) decompose in a Group V just as fast as a Group II and are the fluids first line of defense. Once gone (depleted) the fluid must rely on chemical structure so yea, it last a bit longer but it will not stop speeding bullets or jump tall buildings in a single bound. 


Know what else this processing does to a mineral oil? It breaks it's viscosity to the point than non oil viscosity modifiers which are shear sensitive must be added OR blending with a lower group mineral to bring back the viscosity which also brings back some aromatics. It pollutes it. 


It could also be blended with a PAO which would enhance BOTH viscosity profiles and inhibit oxidation BUT they cost money. Money that is NOT normally used in "Full Synthetic" fluids. 


GM has two part numbers for Dexron VI. One is Synthetic and one is a mineral oil. BOTH meet the low bar of OEM REQUIREMENTS.


Telling a person something is BETTER is not the same thing as making it BETTER. 


Soooooo. What is a fella to do when your not sure you are being lied to or not? What does that mean? Fair question. It means what do you do when you can not tell what a producers FULL SYNTHETIC is made from? Then you treat that product like it is the bottom of the barrel. 




How on earth is this ever bad advice?


When only one person in the room is telling the truth and you don't know who that is, everyone is treated as a liar. Unless they can offer PROOF. 


PROOF is the reason I use Red Line automatic transmission fluids WHEN THEY HAVE ONE FOR THE APPLICATION. Red Line or MPT for manual boxes and diffs. 


When they don't I use something like Valvoline or Castrol and change it like I own the well and add coolers until it will stay under 180 F.


Buy the time you find out the OEM isn't all that and a can of beans following their method; it's damage done and I still pay the price. Been there, done that. Had the Tee shirt...not again. 



  • Like 1
Link to comment
Share on other sites

4 hours ago, elcamino said:





Any 'advertisement' telling even 90% of the story is 100% misleading.






When you finish this article ask yourself if the clutches in this transmission are stock? Was anything in this transmission stock? Was this representative of a typical 6L80 in build or operation? Do you think that matters? Do you think the fluid it in that transmission is the same fluid you buy? 


Mr. there are hindered Polyol Esters in Jet Turbine motors that will take 500 F all day and do it for years. Made by the same company that supplies fluid for automotive use. Both say the same name on the bottle. None of it goes in commercial or retail automotive applications. 



Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Forum Statistics

    Total Topics
    Total Posts
  • Member Statistics

    Total Members
    Most Online
    Newest Member
  • Who's Online   4 Members, 0 Anonymous, 1,362 Guests (See full list)

  • Create New...

Important Information

By using this site, you agree to our Terms of Use.