Transmission Temp?

sdeeter19555 · June 2, 2017

OEM fluids still come from the low bid supplier. While they are adequate, they are not meant to last forever as many seem to think. Your vehicle is not made to last forever. Most people do not like to hear this but the reality is, car/truck/powersports dealers and OEM’s need a reason for owners to keep buying new vehicles otherwise they simply won’t make money.

It is still outdated, when this chart was introduced, Dex III was the standard...now we are at Dex VI which is at least partially synthetic.

So I stand by my statement, it is outdated.

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Grumpy Bear · June 2, 2017

It is still outdated, when this chart was introduced, Dex III was the standard...now we are at Dex VI which is at least partially synthetic.

So I stand by my statement, it is outdated.

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I'd say how "synthetic" was gotten too is HUGE. If my simple molecular rearrangement such as is the case with Mobil 1 motor oil, the chart is pretty good. If by total base stock replacement such as neopentyl glycol then you have a case for obsolete. Dino oil no matter how well refined is still dino juice. Just has a better Noack number and lower pour point.

Take it or leave it as you choose. I got no axes that need a grind.

Edited June 2, 2017 by Grumpy Bear

sdeeter19555 · June 3, 2017

I also want to point.out that chart was made by a transmission rebuilder, what better way to drum up business...

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elchilero53 · July 31, 2017

Drove over to Camping World Friday and it was about 101 to 104 outside temp. The transmission temperature gauge ran at 181 degrees steady at 60 mph up and down some nice hills. The temp would rise to 185 then immediately drop back to 181. This kept up steadily there and back, about 90 miles round trip. I've read comments elsewhere on this forum that said the transmissions now are thermostatically controlled to run a little on the hotter side. That must be true here, though I remain skeptical.

Mr. Z71 · August 6, 2017

I wish I had transmission temp on my 05 truck. I just have to rely on coolant temp when towing the camper. It'll get up to 230deg up long hill stretches pulling 7000lbs. Is there any way to add transmission temp without having to tap a new sensor into the pan?

According to Circuit Board Medics (see link below) if you have a 2003-2006 GM instrument cluster, they can add the gauge to it. They claim that all full size GM vehicles (Silverado, Suburban, Tahoe, Sierra, Yukon, Avalanche, or Denali) already have a transmission temperature sensor and are wired for this gauge from the factory (makes sense otherwise how could they monitor trans temp for vehicle operation/functions, which I'm sure they do). Contact them for more info.

https://circuitboardmedics.com/blog/tag/GM+transmission+temperature+gauge

Big Whiskey · August 7, 2017

Years ago, an old gear-head told me that transmission temps shouldn't get higher than 100 degrees over the outside air temperature. I've always used that as a general rule of thumb. The highest transmission temp I've seen on any of my vehicles is 230, and that was while towing a camper in the mountains of Colorado. I pulled over and let it cool down to 180 before continuing up the mountain.

Spurshot · August 9, 2017

'been jumping around the forums a little. This thread caught my eye. Question for guys that have data on the Dex 6: What's the temp threshold where we should change fluid? (regardless of miles)

centralmepistol · September 6, 2017

After a summer of towing I thought I would fill you all in on my temps...

180's on hot sunny highways.

190's at times in the hils.

Max temp was 205 as I crested a mountain pass. Was planning to pull over and let it cool- but, I was at the top and it cooled just fine as soon as I started the descent.

elchilero53 · September 6, 2017

Drove to New Mexico on vacation towing a 5500 lb travel trailer last Saturday. Air temps were low to mid 90s. Used tow/haul and had cruise control set for 63 mph. Transmission temp stayed between 181 and 185 until I started the long slow climb through the mountains (even going through some pretty good hills crossing the Canadian River north of Amarillo). Hit 191 at the summit of a 9100 ft pass after climbing a 2-mile 7% grade. I wasn't driving very fast (20 mph in 3rd gear) so not getting a lot of air flow through the radiator. Air temp was 62 degrees. Hit 194 degrees using engine grade braking on the down-hill side of the pass (I was in 2nd gear at the time). Coolant tps floated between 205 and 215 degrees the whole way. There were light to moderate cross winds from the north most of the way. No sway issues at all.

Towing was a breeze! The tranny didn't constantly hunt gears. It stayed mostly in 5th but ran for quite a while in 6th. Overall average mileage was 12.5 mpg for the entire trip. Across the plains from Wichita Falls to Amarillo I was getting 13 to 15 mpg but through the hills it dropped back to 10 to 11 mpg.

Engine and tranny worked like a charm!

mookdoc6 · September 6, 2017

Drove to New Mexico on vacation towing a 5500 lb travel trailer last Saturday. Air temps were low to mid 90s. Used tow/haul and had cruise control set for 63 mph. Transmission temp stayed between 181 and 185 until I started the long slow climb through the mountains (even going through some pretty good hills crossing the Canadian River north of Amarillo). Hit 191 at the summit of a 9100 ft pass after climbing a 2-mile 7% grade. I wasn't driving very fast (20 mph in 3rd gear) so not getting a lot of air flow through the radiator. Air temp was 62 degrees. Hit 194 degrees using engine grade braking on the down-hill side of the pass (I was in 2nd gear at the time). Coolant tps floated between 205 and 215 degrees the whole way. There were light to moderate cross winds from the north most of the way. No sway issues at all.

Towing was a breeze! The tranny didn't constantly hunt gears. It stayed mostly in 5th but ran for quite a while in 6th. Overall average mileage was 12.5 mpg for the entire trip. Across the plains from Wichita Falls to Amarillo I was getting 13 to 15 mpg but through the hills it dropped back to 10 to 11 mpg.

Engine and tranny worked like a charm!

Nice to hear! I bet that 6.2L and 8speed works great towing.....my personal favorite feature of mine is coasting down the other side of mountain passes and having complete control of decent without doing anything at all other than steer? Oh, I used to hate driving trucks up and down hills listening to them scream while shifting DOWN,DOWN...UP, DOWN.....arghh

Edited September 6, 2017 by mookdoc6

elchilero53 · September 6, 2017

Yes, the 6.2L/8-speed combo is very nice even without Max Tow (I have the 3.23:1 rear-end). Gotta love it!

Grumpy Bear · September 7, 2017

Drove to New Mexico on vacation towing a 5500 lb travel trailer last Saturday. Air temps were low to mid 90s. Used tow/haul and had cruise control set for 63 mph. Transmission temp stayed between 181 and 185 until I started the long slow climb through the mountains (even going through some pretty good hills crossing the Canadian River north of Amarillo). Hit 191 at the summit of a 9100 ft pass after climbing a 2-mile 7% grade. I wasn't driving very fast (20 mph in 3rd gear) so not getting a lot of air flow through the radiator. Air temp was 62 degrees. Hit 194 degrees using engine grade braking on the down-hill side of the pass (I was in 2nd gear at the time). Coolant tps floated between 205 and 215 degrees the whole way. There were light to moderate cross winds from the north most of the way. No sway issues at all.

Towing was a breeze! The tranny didn't constantly hunt gears. It stayed mostly in 5th but ran for quite a while in 6th. Overall average mileage was 12.5 mpg for the entire trip. Across the plains from Wichita Falls to Amarillo I was getting 13 to 15 mpg but through the hills it dropped back to 10 to 11 mpg.

Engine and tranny worked like a charm!

I know this is a trans temp thread but...you need to be looking at the engine oil temps. Done it and it is scary.

elchilero53 · September 7, 2017

Gosh, let's not go there. No one will want to drive their trucks anymore.

Mine has the engine oil cooler and that probably helps somewhat.

sdeeter19555 · September 7, 2017

I know this is a trans temp thread but...you need to be looking at the engine oil temps. Done it and it is scary.

Not really scary at all...I've only ever seen over 235F once; and that was towing 6000#s, over a 6 to 9% grade, for about three miles, with ambient temperature around 100F. Most times it runs between 204 and 210...most quality 5w30 oils are good to around 275 to 300F.

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