Transmission Temperature - What is considered "Hot"?

Drifthopper · July 24, 2012

What is considered a "Hot" transmission temperature?

2012 GMC Sierra 5.3 with tow package.

Now.... i'm not towing anything as big as others on here, and not goin' thru the mid-west, just wondering at what temp should one start to be concerned and maybe pull over.

For you Eastern's out there, went camping to the 1000 Islands, towing a pop-up camper,(2200, maybe 2500 lbs.) truck loaded with firewood and camping stuff, about 90 -92 degrees out , east down the 90 north on the 81, stopped in Central Square for a coffee and when pulling out of the drive thru i noticed 183 /184 on the digital read out for my trans temp.

What's a "Hot" trans temperature?

Sir Dan · July 24, 2012

180-190 degs is the highest mine ever gets even when towing big items. The manual says that the computer will warn you "TRANSMISSION HOT IDLE ENGINE" in the DIC but doesn't say what temp triggers it. I would be interested to know that as well. Having a trans temp indication is nice, but it would be better to have a normal range specified.

00Silverado4x4 · July 24, 2012

Somewhere on here I've read that there is no need for concern until you reach ~240F. Is that fact...nope, don't have that information available. However if you're only hauling 2k, maybe 2.5k lbs plus some gear in the bed, I don't think you have much to worry about. Just an opinion.

hodo78 · July 24, 2012

My tranny will reach 185F in 95F heat when only hauling my 600lb ATV in the bed. My truck has the 5.3, 3.42, towing package. And this is normal 40-50 mph driving on a two lane with rolling hills.

Chris · July 24, 2012

Ill hit about 200F in 110F weather towing a 2 horse trailer

tyhuck · July 24, 2012

from what I can remember, you dont have anything to worry about till you get to 225+. If you get to 250, pull over ASAP.

I could be wrong though.

CKNSLS · July 25, 2012

Hauled my 5,000 pound 28 foot travel trailer from So. Cal to Utah a couple of weeks ago. Ambient temperature was 105 degrees outside. So the transmission was running in the 180s to 190s. Going up over two 6,000 feet mountain passes it reached 235. No display from DIC mentioning I was too hot.

No issues with the 600 mile trip with truck or trailer.

The new transmission fluid in the new 6 speeds can take the heat.

MikeNH · July 25, 2012

x2. The 6-speeds run a bit hotter but with synthetic trans fluid it's supposed to be okay.

zibzer · July 25, 2012

Had my 2000 Silverado get up to 210 many times while towing in hot summer weather. Had 310,000km (192,000miles) transmission never gave me a lick of trouble in all those miles.. By the end when I traded it in everything else had given me minor issues. But the tranny was rock solid.

IMHO i would change fluid and filter fairly often if you hit these temps on a regular basis

mc7719 · July 25, 2012

Towing about 6500lbs (travel trailer) on a long uphill stretch in 31C (90F) August temperatures, it hit 110C (230F) for a short while and no warnings... however at the top I did pull out and let it idle for some time until the temp lowered. Maybe once or twice in a whole year will I hit that. Before I had left, I ensured the trans service was done, and when I got home, had it checked out and the fluid still looked and smelled new.

dsblue2000 · August 1, 2012

My 2005 5.3L Tahoe owner's manual refers to "normal operating temperature" as 180-200 degrees F. I can drive days in summer weather (not towing) and it only occasionally reaches 180-185 (I added an aeroforcetech gauge that displays trans temp). Cold weather it can hover 130-150 even on hills and only reaches "normal" temperature when idling for 10-15 minutes or on very long hills.

I also tow a 19' TT, loaded about 5,000lbs. Trans temps often rose above 200 (I saw 220 once on a long, steep grade in 2nd gear) when I had 3.42 gears. I regeared to 4.11. Now most hills in even in hot weather trans temps reach 200, 205, and but only occasionally 210. Airflow through the factory trans cooler seems critical.

I seem to remember a GM trans tech telling me that you "don't start to burn trans oil" until 250 but I can't be sure of that number (maybe 240?). I just remember it was a ways above the 220 I mentioned to him.

shenandoah75 · August 2, 2012

I got the TRANSMISSION HOT on the DIC one time. Got stuc in a dead end residential neighborhood from poorly labeled signs to a state park. Backing up with a 6000 lb travel trailer on hills apparently heats up quick,

CKNSLS · August 2, 2012

I got the TRANSMISSION HOT on the DIC one time. Got stuc in a dead end residential neighborhood from poorly labeled signs to a state park. Backing up with a 6000 lb travel trailer on hills apparently heats up quick,

Anybody know in the new trucks /w six speed know when the "Transmission Hot" message is display? At what temp? It's not 235 degrees because I have hit that mark with no message.

Gurrzt · August 3, 2012

210F is when transmission fluid starts to burn and degrade.

You can add a deeper transmission pan along with an external cooler (if you do not have one), B&M has a 24k with a mounted fan that will do the job for you.

Your routing would be:

Out of the trans, into the radiator, out of the radiator into the external cooler, out of the cooler back to the transmission.

00Silverado4x4 · August 3, 2012

210F is when transmission fluid starts to burn and degrade.

You can add a deeper transmission pan along with an external cooler (if you do not have one), B&M has a 24k with a mounted fan that will do the job for you.

Your routing would be:

Out of the trans, into the radiator, out of the radiator into the external cooler, out of the cooler back to the transmission.

Curious as to where you found the 210 number? Seems awfully low since it's known that several of us have reach and exceeded that number and show no sign of fluid burn in our transmissions? Not starting an argument, I honestly curious.