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8l90 transmission working temp

Giantpeaches
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Giantpeaches Enthusiast

Giantpeaches

Posted
Posted (edited)

Recently bought 2019 Silverado lt trailboss with 5.3 and 8spd tranny

 

What's the normal operating temp for 8speed transmission? Not towing but just driving in the city/hwy. I'm getting between 70-85 deg Celsius or 158-185 deg f.

 

Also noticed temp went really high while driving in the moderately deep snow on the back road in 4hi. 140deg Celsius! Which I think is 290f.

 

Are these temps normal? 

 

Coming off dodge  with 5spd tranny it was running at 50 for normal use and Max of 80deg Celsius these high temps are new to me, unsure if it's even normal?

 

Truck only has 1300km 

IMG_20200222_092140.jpg

Edited by Giantpeaches
Rick Franklin Enthusiast

Rick Franklin

Posted
Posted

That sounds high. At 285F you are close to burning the fluid although, the gauge/sensor may be inaccurate, I would get it back to the dealer.

Black02Silverado Senior Enthusiast

Black02Silverado

Posted
Posted

That doesn't sound right.  If it truly was that high something is wrong.  I would think it would have thrown a code.  How long of a drive in the deep snow?

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Giantpeaches Enthusiast

Giantpeaches

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Posted (edited)
19 hours ago, Black02Silverado said:

That doesn't sound right.  If it truly was that high something is wrong.  I would think it would have thrown a code.  How long of a drive in the deep snow?

Yeah.. I figured it would throw a code but it was definitely 145deg C. I should've taken some pictures at the time but didn't think to.

 

I'd say about 1-2km/ 1.2 miles? till I decided to turn around and go back.

 

not sure if tech can plug in obd reader and pull some historical data or anything.. 

 

Meant to drop it off tomorrow to have couple of things looked at.

 

 

Edited by Giantpeaches
BlancoSilverado Enthusiast

BlancoSilverado

Posted
Posted

At 290f you cooked all your fluid and probably want  a new trans. Probably a sensor issue. let it sit all night and check the temp in the morning, it should be within 10 degrees of the outside temp.(actual temp not the trucks outside temp).

Black02Silverado Senior Enthusiast

Black02Silverado

Posted
Posted

What does the fluid look like?  At that temp like posted above I would think it would have effected the color and no longer be a nice pink color.

Giantpeaches Enthusiast

Giantpeaches

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Posted
1 hour ago, BlancoSilverado said:

At 290f you cooked all your fluid and probably want  a new trans. Probably a sensor issue. let it sit all night and check the temp in the morning, it should be within 10 degrees of the outside temp.(actual temp not the trucks outside temp).

since then it's been running normally. I don't exactly know what the normal temperature for city/hwy driving is for these trucks and tranny but I find it runs between 140-180F

 

Giantpeaches Enthusiast

Giantpeaches

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27 minutes ago, Black02Silverado said:

What does the fluid look like?  At that temp like posted above I would think it would have effected the color and no longer be a nice pink color.

Is there way to check fluid color on these 8 spd transmission? I just know there's no dipstick to check the level or anything

Black02Silverado Senior Enthusiast

Black02Silverado

Posted
Posted
1 minute ago, Giantpeaches said:

Is there way to check fluid color on these 8 spd transmission? I just know there's no dipstick to check the level or anything

There is an inspection port so to speak on the side basically where a dipstick tube would go.  There is a plug over it.  Could pull the plug to check.

Giantpeaches Enthusiast

Giantpeaches

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  • Author
Posted

Just heard back from the dealer and they couldn't pull any codes or parameters all seem normal and he assured me 140-180 is normal operating temperature.. I asked in Celsius or Fahrenheit? and he said celsius.. seems wrong.... 

  • 2 years later...
Reno Silverado New Member

Reno Silverado

Posted
Posted

To check trans temp, scroll through drivers info steering wheel, there is one blank screen before the trans temp screen. My truck has a trans oil cooler, I think, and you would think the trans temp would be cooler than 180 degrees F, with an ambient temperature of 40-50 degrees F, and an unloaded truck.

Byrds8 Enthusiast

Byrds8

Posted
Posted

I definitely have a transmission oil cooler but it doesn't seem to change my temps. I don't think anything is going to keep them lower considering they have a thermostat that keeps them pretty warm. I could be wrong though lol.

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