Had a question about transmission temps. Its in a 2013 Tahoe. I believe it’s the 6L80. 58K miles. Anyways, on the highway I’m seeing the temp gauge anywhere from 100-120 degrees but if it’s sitting in a parking lot it climbs up to 160+…is this normal? Will it continue to keep climbing if i leave it idling or does it eventually settle out? I pulled the dipstick last night when it was around 170 degrees and fluid was pretty much in the middle of the “hot” cross hatch marking.
Transmission Question
- Thread starter Landonz
- Start date
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Yup, normal. Your external transmission fluid cooler is in front of the radiator, so when the vehicle is moving it’s receiving more airflow.
For what is worth, GM recommends a minimum 6L80E fluid temperature for continuous operation to be 150°F. Maximum is 265°F
intheburbs
Full Access Member
Typically, they'll run about 100° over ambient. Maybe a little more.
"Normal operating temperature" is 190°-200°. Dex6 is some pretty good stuff.
You don't get the "trans hot idle engine" warning until about 265°.
When towing, I've had my Suburban as high as 243°. 225k miles, original transmission.
I like to post this pic to make heads explode.
"Normal operating temperature" is 190°-200°. Dex6 is some pretty good stuff.
You don't get the "trans hot idle engine" warning until about 265°.
When towing, I've had my Suburban as high as 243°. 225k miles, original transmission.
I like to post this pic to make heads explode.
swathdiver
Full Access Member
Normal, probably cold where you are this time of year. Get ahead of the game and change the fluid in it now, we all run severe service and need to change it before 45K or so miles.
I changed the fluid and filter at 55k. How often is it recommended?
Depends on what you're doing with it. @swathdiver has had oil analysis done on his fluid and has better info, but I tow a lot with our 2012 XL Denali and change the fluid every 20K miles. I seldom tow with our 2007 XL Denali, and plan to change it every 35K miles. I have the filters changed every other fluid change.
I've had similar temps in mine when towing heavy over the mountains (high 230's IIRC). I see just as much heat towing in the Appalachians in summer as I do in the Rockies.Typically, they'll run about 100° over ambient. Maybe a little more.
"Normal operating temperature" is 190°-200°. Dex6 is some pretty good stuff.
You don't get the "trans hot idle engine" warning until about 265°.
When towing, I've had my Suburban as high as 243°. 225k miles, original transmission.
I like to post this pic to make heads explode.
intheburbs
Full Access Member
According to the owner's manual, for "normal" vehicle use, every 100k miles. For "severe" use, every 50k. But if you look up GM's definition of "normal" and "severe," the vast majority are "severe."
Myself, I do every 50k at a minimum. And I take it to the dealer for a full flush - all 16 quarts. My shortest inverval was 30k, when I took several trips out West with my 8600-lb travel trailer in one summer. It hits those stupid temperatures when climbing the Continental Divide. That pic was from ascending towards the Eisenhower Tunnel, long 7% grade, elevation 11,000 ft.
Trans fluid is easy to maintain. Pull the dipstick, smell it, rub it on your fingers, and put a drop on a piece of white paper towel. If it's bright red, smells hydraulicky/detergenty, and still feels like oil with no grit, it's good. If it's starting to turn brown (or worse), smells burned, or is gritty, replace it.
This thread reminded me to check my fluid in the Suburban. See pic below. The fluid has 33k miles on it. Zero towing over that time, but lots of high-speed (85-100+) cruising. I also splashed on some new fluid for contrast/comparison. It looks/smells/feels as I'd expect for that mileage. Still smells detergenty, nice and smooth between my fingers, lost some of the bright red color. I'm confident letting it go to 50k. Unless a towing trip pops up on my schedule, then I'll flush it before I head out.
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swathdiver
Full Access Member
GM recommends every 45K for yours. Sent off a sample to Blackstone Labs for analysis a few years ago. At the time, the fluid had 36K on it and about a weeks worth of around town towing at 4K-5K pounds. They said the fluid was good for another 10K miles.
There's a guy on here with a 2008 Denali who shared with us his maintenance log since new and at the time he had about 190K on it. He changed the fluid every 42K miles, religiously. Still going strong. Trevor was his name, Mr T. was his screen name or something similar, haven't seen him in a while.
Anyway, after those two events, I think it good practice to change it between 36-45K unless you do towing, then I would do it even sooner, or like Bill mentioned, after a hot pull even.
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