6L80 Heat Related Symptoms

[Fless]

2017 - didn't know the thread was for those years.

I'm still wondering how the trans temp can EVER go below the radiator temps, if it's part of that system

T-stat would run it cool until the radiator temps came up to 210, then I'd be at 210 anyways -right?

Probably best to stick with your post in the correct year, as there may be differences.

Overheating 6L80e

You're way over thinking this...Fluid is a much more efficient heat exchanger than air so by eliminating the fluid's travel through the radiator's internal transmission cooler, you've cut your cooling efficiency by at least 50% or so.... I'm hitting 230 occasionally in Florida stop and go...

www.tahoeyukonforum.com

 

[Foggy]

2017 - didn't know the thread was for those years.

I'm still wondering how the trans temp can EVER go below the radiator temps, if it's part of that system

T-stat would run it cool until the radiator temps came up to 210, then I'd be at 210 anyways -right?

Yes. The trans temp usually is lower than the coolant. The coolant in your radiator
is constantly PULLING Heat from the Trans Fluid and transferring it to the coolant
where your radiator/coolant/fan keep it in check
And you are probably NOT running at 210* unless you are in stop and go traffic
and/or very hot situations or have a poorly maintained cooling system.

 

[TahoeFL2017]

Yes. The trans temp usually is lower than the coolant. The coolant in your radiator
is constantly PULLING Heat from the Trans Fluid and transferring it to the coolant
where your radiator/coolant/fan keep it in check
And you are probably NOT running at 210* unless you are in stop and go traffic
and/or very hot situations or have a poorly maintained cooling system.

I just hit 244 driving lightly with the ac on, 88 degrees outside.

 

[Geotrash]

I just hit 244 driving lightly with the ac on, 88 degrees outside.

Definitely need a cooler on that thing

 

[j91z28d1]

2017 - didn't know the thread was for those years.

I'm still wondering how the trans temp can EVER go below the radiator temps, if it's part of that system

T-stat would run it cool until the radiator temps came up to 210, then I'd be at 210 anyways -right?

trannys cooler is in the cooled side of the radiator, after it exits the engine at 210 on the drivers side, the radiator drops the Temps down and that's side is where your trans cooler is. also the engine cooling system with the thermostat will basically bypass the radiator and just circle water around in it thru the heater core to keep the engine up to temp, as the radiator fans have to run all the time for the ac, it would over cool the engine if coolent run thru it at 100%. if you buy one of those thermal heat guns, you can test around didn't spots and find the Temps.

the engine coolent Temps sensor might be be in a different location on your newer LT engine, but our older ls it's in the cylinder head which is the hottest place. I've seen a very large difference in the temp at the cylinder head, to the cool side of the radiator.

 

[TahoeFL2017]

Definitely need a cooler on that thing

I put the thermal bypass on about 5 months ago, so this is the first time in warmer weather.

WTF do you think is causing 240 degrees now? Radiator issues maybe?

Crazy that it's this hot in city driving, I literally drove 20 minutes to Lowe's and just randomly checked it on the way home, and it's at 244.

Fluid looks normal, shifts fine. Might have been 240 all the way to Georgia a few weeks ago, didn't check it all day.

 

[Foggy]

I put the thermal bypass on about 5 months ago, so this is the first time in warmer weather.

WTF do you think is causing 240 degrees now? Radiator issues maybe?

Crazy that it's this hot in city driving, I literally drove 20 minutes to Lowe's and just randomly checked it on the way home, and it's at 244.

Fluid looks normal, shifts fine. Might have been 240 all the way to Georgia a few weeks ago, didn't check it all day.

I bet your fans aren't working correctly !!! OR you still have trapped air inthe
cooling system. Maybe try re burping the system again. And really observe
if the fans have LOW and HIGH speed. They should both come on at the same
time. First they come on on LOW speed, then if needed the HIGH kicks in
OR when the AC is on sitting still they should eventually come on HIGH

 

[j91z28d1]

is it possible the tranny line stat is backward?? I thought most just removed that thing.


you are taking tranny Temps not coolent Temps right?

 

[TahoeFL2017]

is it possible the tranny line stat is backward?? I thought most just removed that thing.


you are taking tranny Temps not coolent Temps right?

I'm starting to think the t-stat was either installed wrong, or is sticking, and I just didn't see high temps until it got hot recently.

It gets hot very slowly steadily, as if the fluid is just staying in the trans and never getting to the cooler.

It takes 30 minutes of driving in 80+ degrees to break 200 degrees, then slowly but surely hits 20, 230, 240

Definitely trans fluid, right on my display.

Shifts completely fine, doesn't slip, you'd never know anything without looking at the temp readout..

But - I think I smell a faint odor of anti-freeze, so this might be something amiss in my radiator - but engine temps are steady.

 

[B-train]

How long does it take to get the AT up to 200F?

Do you have a factory cooler, or any cooler installed?

Holy Cow! I just did over 3k miles round trip to ID and back with 3000 lbs in tow and never went over 160F with mountain driving. My 2008 doesn't have the trans thermostat, so I think that's the key. Flip the pill or eliminate it with older model year cooler lines. A trans doesn't need to be 200F on a regular basis.