Trans fluid temp?

Loco Diablo · August 16, 2018

Just for grins, I thought I’d monitor my trans temp on the way to work today.
During my 30 mile commute I was average highway speed of 70/75 mph, rpm averaged 1750, ambient temp was about 75 Fahrenheit. No load in the truck. The fluid temp seemed to top around 175 degrees on the highway. Once off the highway, I have about an additional 1.5 miles of stop and go back roads where the temp climbed to about 180. Once parked, I monitored it for another 10 minutes where it went to 185 and stayed around there.

2017, Silverado 1500, DC, 4x4, 5.3, 6speed.

What is the normal temp range?

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Spurshot · August 16, 2018

http://transmissionrepairguy.com/transmission-temperature-gauge/

newdude · August 16, 2018

43 minutes ago, Loco Diablo said:

Just for grins, I thought I’d monitor my trans temp on the way to work today.
During my 30 mile commute I was average highway speed of 70/75 mph, rpm averaged 1750, ambient temp was about 75 Fahrenheit. No load in the truck. The fluid temp seemed to top around 175 degrees on the highway. Once off the highway, I have about an additional 1.5 miles of stop and go back roads where the temp climbed to about 180. Once parked, I monitored it for another 10 minutes where it went to 185 and stayed around there.

2017, Silverado 1500, DC, 4x4, 5.3, 6speed.

What is the normal temp range?

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Normal. The transmissons on K2 are thermostatically regulated. Opens up at a set temperature to run fluid to the coolers. They run typically 175-200F during driving, and usually get there quick. Fuel economy reasons...less friction in the driveline when the fluids are up to temp. You could see up to 230F towing. Overheat comes on at 260F.

The HD trucks are continuous flow, no thermostat.

Edited August 16, 2018 by newdude

mookdoc6 · August 16, 2018

Thanks! Now I have something to go by? I will be installing a new Harness and fluid sensor next week and changing fluid etc. Obviously mine reads all over the place........

Loco-diablo · August 16, 2018

Thanks all for the feedback. Good to know it's operating correctly.

Grumpy Bear · August 16, 2018

3 hours ago, Spurshot said:

http://transmissionrepairguy.com/transmission-temperature-gauge/

That is a great resource and on the money. Thank you Spurshot!!!!

Sgonza101 · August 16, 2018

My 17 z71 5.3 4x4 pulling about 2000 lbs, 6 passengers, and a bed full of camping gear. Was getting the temp at around 224F. That was pulling up hill and at a average speed of 30 mph. The ambient temp was about 98F.

swathdiver · August 16, 2018

10 hours ago, Loco Diablo said:

2017, Silverado 1500, DC, 4x4, 5.3, 6speed.

What is the normal temp range?

Read the shop manual for the latest numbers on your K2. For the GMT900 with same transmission, the normal operating range is between 160 and 200 degrees. The high temperature alerts and codes don't happen until the fluid gets to 266 and 270.

Mine, with 3.42 gears and the factory external cooler runs 156 @ 92 outside while running 75 mph and will climb to 176 once off the highway. The only time it's been higher was the day the fluid exchange was done and it was 100 degrees out and while drag racing.

Edited August 16, 2018 by swathdiver
grammar

Loco Diablo · August 17, 2018

Read the shop manual for the latest numbers on your K2. For the GMT900 with same transmission, the normal operating range is between 160 and 200 degrees. The high temperature alerts and codes don't happen until the fluid gets to 266 and 270.

Mine, with 3.42 gears and the factory external cooler runs 156 @ 92 outside while running 75 mph and will climb to 176 once off the highway. The only time it's been higher was the day the fluid exchange was done and it was 100 degrees out and while drag racing.

Wow.. that seems cool. What year? I have the 3.42 also with Z82 factory trailering package. Does that come with the external cooler?

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swathdiver · August 17, 2018

13 minutes ago, Loco Diablo said:

Wow.. that seems cool. What year? I have the 3.42 also with Z82 factory trailering package. Does that come with the external cooler?

2009 GMC Yukon XL. Z82 does not determine whether or not it has the transmission cooler. I think for yours it would be part of NHT package but it could also have it separate, not sure. Anyways, the RPO code for the external trans cooler is KNP.

Loco Diablo · August 17, 2018

2009 GMC Yukon XL. Z82 does not determine whether or not it has the transmission cooler. I think for yours it would be part of NHT package but it could also have it separate, not sure. Anyways, the RPO code for the external trans cooler is KNP.

Yup... KNP Transmission oil cooler is on my build sheet

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14 gmcl83 · August 17, 2018

My transmission temps run between 140-170 in Florida heat. But I also delete the t-stat in the trans cooler lines before it was 195-205 my

trucks 14 5.3 4x4 z71 slt 3.42 gears g80 posi

Grumpy Bear · August 17, 2018

1 hour ago, 14 gmcl83 said:

My transmission temps run between 140-170 in Florida heat. But I also delete the t-stat in the trans cooler lines before it was 195-205 my

trucks 14 5.3 4x4 z71 slt 3.42 gears g80 posi

Yea, what he said but mine pre delete would hit 225/230 pretty easy pulling 5-7% grades on hot days. Low 200's was usual.

mookdoc6 · August 24, 2018

Finally had the wiring harness/sensor installed. I now watch the Trans temp it is now acting accordingly......It reads 110f in morning and tops out now 185F before being T-Stated......Readings are not 82f constant then after 30 minutes jump to 160f and never read higher? All good in the ECOTECH!